CIRRUS CS4525

CS4525
30 W Digital Audio Amplifier with Integrated ADC
Digital Amplifier Features
ADC Features
Fully Integrated Power MOSFETs
Stereo, 24-bit, 48 kHz Conversion
No Heatsink Required
Multi-bit Architecture
–
–
95 dB Dynamic Range (A-wtd)
Programmable Power Foldback on
Thermal Warning
High Efficiency
-86 dB THD+N
Supports 2 Vrms Input with Passive
Components
> 100 dB Dynamic Range
< 0.1% THD+N @ 1 W
System Features
Configurable Outputs (10% THD+N)
Asynchronous 2-channel Digital Serial Port
–
–
–
1 x 30 W into 4 Ω, Parallel Full-Bridge
2 x 15 W into 8 Ω, Full-Bridge
2 x 7 W into 4 Ω, Half-Bridge + 1 x 15 W
into 8 Ω, Full-Bridge
32 kHz to 96 kHz Input Sample Rates
Operation with On-chip Oscillator Driver or
Applied SYS_CLK at 18.432, 24.576 or
27.000 MHz
Integrated Sample Rate Converter (SRC)
– Eliminates Clock-jitter Effects
– Input Sample Rate Independent Operation
– Simplifies System Integration
Built-In Protection with Error Reporting
–
–
Overcurrent / Undervoltage / Thermal
Overload Shutdown
Thermal Warning Reporting
Spread Spectrum PWM Modulation
PWM Popguard® for Half-Bridge Mode
–
Click-free Start-up
Reduces EMI Radiated Energy
Low Quiescent Current
Programmable Channel Delay for System
(Features continued on page 2)
Noise & Radiated Emissions Management
2.5 V to 5 V
8 V to 18 V
VP
System Clock
Crystal Driver
I/O
Audio
Processing
Amplifier
Out 1
Gate
Drive
Amplifier
Out 2
Gate
Drive
Amplifier
Out 3
Gate
Drive
Amplifier
Out 4
Crystal Oscillator Driver
Parametric EQ
High-Pass
Stereo
Analog In
Serial Audio
Clocks & Data
PWM
Gate
Drive
Multi-bit ∆Σ ADC
Serial Audio Input Port
Multi-bit ∆Σ
Modulator
Bass/Treble
Adaptive
Loudness
Compensation
with
2-Ch Mixer
Serial Audio
Data I/O
Serial Audio
Clocks & Data
Serial Audio
Delay Interface
2.1 Bass Mgr
Auxiliary Serial Port
De-Emphasis
Linkwitz-Riley
Crossover
Integrated
Sample Rate
Converter
Volume
HP Detect/Mute
Reset
Interrupt
PGND
Error Protection
Register /Hardware
Configuration
I²C or Hardware
Configuration
Preliminary Product Information
http://www.cirrus.com
Thermal Warning
Over Current
Thermal Feedback
Under Voltage
PWM Modulator
Output 1
PWM Modulator
Output 2
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
Copyright © Cirrus Logic, Inc. 2008
(All Rights Reserved)
JUL '08
DS726PP3
CS4525
Software Mode System Features
Common Applications
Digital Audio Processing
Integrated Digital TV’s
–
–
–
–
–
–
–
–
5 Programmable Parametric EQ Filters
Selectable High-pass Filter
Bass/Treble Tone Control
Adaptive Loudness Compensation
2-channel Mixer
2.1 Bass Management
24 dB/octave Linkwitz-Riley Crossover
Filters
De-emphasis Filter
Selectable Serial Audio Interface Formats
–
–
–
Left-justified up to 24-bit
I²S up to 24-bit
Right-justified 16-, 18-, 20-, 24-bits
Digital Serial Connection to Additional CS4525
or DACs for Subwoofer
Digital Interface to External Lip-sync Delay
PWM Switch Rate Shifting Eliminates AM
Frequency Interference
Digital Volume Control with Soft Ramp
– +24 to -103 dB in 0.5 dB steps
Programmable Peak Detect and Limiter
2-Channel Logic-level PWM Output
–
–

Programmable Channel Mapping
Can Drive an External PWM Amplifier,
Headphone Amplifier, or Line-out Amplifier
– Integrated Headphone Detection
Flexible Power Output Configurations
Thermal Foldback for Interruption-free
Power-stage Protection
– Supports Internal and External Power
Stages
Operation from On-chip Oscillator Driver or
Applied Systems Clock
Supports I²C® Host Control Interface
Hardware Mode System Features
2-Channel Stereo Full Bridge Power Outputs
Analog and Digital Inputs
I²S and Left-justified Serial Input Formats
Thermal Foldback for Interruption-free
Protection of Internal Power Stage
Operation from Applied Systems Clock
External Mute Input
2
Flat Panel TV Monitors
Computer/TV Monitors
Mini/Micro Shelf Systems
Digital Powered Speakers
Portable Docking Stations
Computer Desktop Audio
General Description
The CS4525 is a stereo analog or digital input PWM
high efficiency Class D amplifier audio system with an
integrated stereo analog-to-digital (A/D) converter. The
stereo power amplifiers can deliver up to 15 W per
channel into 8 Ω speakers from a small space-saving
48-pin QFN package. The PWM amplifier can achieve
greater than 85% efficiency. The package is thermally
enhanced for optimal heat dissipation which eliminates
the need for a heatsink.
The power stage outputs can be configured as two fullbridge channels for 2 x 15 W operation, two half-bridge
channels
and
one
full-bridge
channel
for
2 x 7 W + 1 x 15 W operation, or one parallel full-bridge
channel for 1 x 30 W operation. The CS4525 integrates
on-chip over-current, under-voltage, and over-temperature protection and error reporting as well as a thermal
warning indicator and programmable foldback of the
output power to allow cooling.
The main digital serial port on the CS4525 can support
asynchronous operation with the integrated on-chip
sample rate converter (SRC) which eases system integration. The SRC allows for a fixed PWM switching
frequency regardless of incoming sample rate as well
as optimal clocking for the A/D modulators.
An on-chip oscillator driver eliminates the need for an
external crystal oscillator circuit, reducing overall design
cost and conserving circuit board space. The CS4525
automatically uses the on-chip oscillator driver in the
absence of an applied master clock.
The CS4525 is available in a 48-pin QFN package in
Commercial grade (0° to +70° C). The CRD4525-Q1 4layer, 1 oz. copper and CRD4525-D1 2-layer, 1 oz. copper customer reference designs are also available.
Please refer to “Ordering Information” on page 97 for
complete ordering information.
DS726PP3
CS4525
TABLE OF CONTENTS
1. PIN DESCRIPTIONS - SOFTWARE MODE .......................................................................................... 8
2. PIN DESCRIPTIONS - HARDWARE MODE ....................................................................................... 10
2.1 Digital I/O Pin Characteristics ........................................................................................................ 12
3. TYPICAL CONNECTION DIAGRAMS ................................................................................................. 13
4. TYPICAL SYSTEM CONFIGURATION DIAGRAMS ........................................................................... 15
5. CHARACTERISTICS AND SPECIFICATIONS .................................................................................... 18
6. APPLICATIONS ................................................................................................................................... 26
6.1 Software Mode ............................................................................................................................... 26
6.1.1 System Clocking ................................................................................................................... 26
6.1.1.1 SYS_CLK Input Clock Mode .................................................................................... 26
6.1.1.2 Crystal Oscillator Mode ............................................................................................ 27
6.1.2 Power-Up and Power-Down ................................................................................................. 28
6.1.2.1 Power-Up Sequence ................................................................................................ 28
6.1.2.2 Power-Down Sequence ............................................................................................ 28
6.1.3 Input Source Selection .......................................................................................................... 29
6.1.4 Digital Sound Processing ...................................................................................................... 29
6.1.4.1 Pre-Scaler ................................................................................................................. 30
6.1.4.2 Digital Signal Processing High-Pass Filter ............................................................... 30
6.1.4.3 Channel Mixer .......................................................................................................... 30
6.1.4.4 De-Emphasis ............................................................................................................ 31
6.1.4.5 Tone Control ............................................................................................................. 31
6.1.4.6 Parametric EQ .......................................................................................................... 33
6.1.4.7 Adaptive Loudness Compensation ........................................................................... 34
6.1.4.8 Bass Management .................................................................................................... 35
6.1.4.9 Volume and Muting Control ...................................................................................... 36
6.1.4.10 Peak Signal Limiter ................................................................................................. 37
6.1.4.11 Thermal Limiter ....................................................................................................... 39
6.1.4.12 Thermal Foldback ................................................................................................... 40
6.1.4.13 2-Way Crossover & Sensitivity Control ................................................................... 42
6.1.5 Auxiliary Serial Output .......................................................................................................... 43
6.1.6 Serial Audio Delay & Warning Input Port .............................................................................. 44
6.1.6.1 Serial Audio Delay Interface ..................................................................................... 44
6.1.6.2 External Warning Input Port ..................................................................................... 44
6.1.7 Powered PWM Outputs ........................................................................................................ 45
6.1.7.1 Output Channel Configurations ................................................................................ 45
6.1.7.2 PWM Popguard Transient Control ............................................................................ 45
6.1.8 Logic-Level PWM Outputs .................................................................................................... 46
6.1.8.1 Recommended PWM_SIG Power-Up Sequence for an External PWM Amplifier .... 47
6.1.8.2 Recommended PWM_SIG Power-Down Sequence for an External PWM Amplifier 47
6.1.8.3 Recommended PWM_SIG Power-Up Sequence for Headphone & Line-Out .......... 48
6.1.8.4 Recommended PWM_SIG Power-Down Sequence for Headphone & Line-Out ..... 48
6.1.8.5 PWM_SIG Logic-Level Output Configurations ......................................................... 49
6.1.9 PWM Modulator Configuration .............................................................................................. 50
6.1.9.1 PWM Channel Delay ................................................................................................ 50
6.1.9.2 PWM AM Frequency Shift ........................................................................................ 51
6.1.10 Headphone Detection & Hardware Mute Input ................................................................... 51
6.1.11 Interrupt Reporting .............................................................................................................. 53
6.1.12 Automatic Power Stage Shut-Down ................................................................................... 53
6.2 Hardware Mode ............................................................................................................................. 54
6.2.1 System Clocking ................................................................................................................... 54
6.2.2 Power-Up and Power-Down ................................................................................................. 54
6.2.2.1 Power-Up Sequence ................................................................................................ 54
DS726PP3
3
CS4525
6.2.2.2 Power-Down Sequence ............................................................................................ 55
6.2.3 Input Source Selection .......................................................................................................... 55
6.2.4 PWM Channel Delay ............................................................................................................ 55
6.2.5 Digital Signal Flow ................................................................................................................ 56
6.2.5.1 High-Pass Filter ........................................................................................................ 56
6.2.5.2 Mute Control ............................................................................................................. 56
6.2.5.3 Warning and Error Reporting .................................................................................... 56
6.2.6 Thermal Foldback ................................................................................................................. 57
6.2.7 Automatic Power Stage Shut-Down ..................................................................................... 58
6.3 PWM Modulators and Sample Rate Converters ............................................................................ 58
6.4 Output Filters ................................................................................................................................. 59
6.4.1 Half-Bridge Output Filter ....................................................................................................... 59
6.4.2 Full-Bridge Output Filter (Stereo or Parallel) ........................................................................ 60
6.5 Analog Inputs ................................................................................................................................. 61
6.6 Serial Audio Interfaces ................................................................................................................... 62
6.6.1 I²S Data Format .................................................................................................................... 62
6.6.2 Left-Justified Data Format .................................................................................................... 62
6.6.3 Right-Justified Data Format .................................................................................................. 63
6.7 Integrated VD Regulator ................................................................................................................ 63
6.8 I²C Control Port Description and Timing ........................................................................................ 64
7. PCB LAYOUT CONSIDERATIONS ..................................................................................................... 65
7.1 Power Supply, Grounding .............................................................................................................. 65
7.2 Output Filter Layout ....................................................................................................................... 65
7.3 QFN Thermal Pad .......................................................................................................................... 65
8. REGISTER QUICK REFERENCE ........................................................................................................ 66
9. REGISTER DESCRIPTIONS ................................................................................................................ 69
9.1 Clock Configuration (Address 01h) ................................................................................................ 69
9.1.1 SYS_CLK Output Enable (EnSysClk) ................................................................................... 69
9.1.2 SYS_CLK Output Divider (DivSysClk) .................................................................................. 69
9.1.3 Clock Frequency (ClkFreq[1:0]) ............................................................................................ 69
9.1.4 HP_Detect/Mute Pin Active Logic Level (HP/MutePol) ......................................................... 70
9.1.5 HP_Detect/Mute Pin Mode (HP/Mute) .................................................................................. 70
9.1.6 Modulator Phase Shifting (PhaseShift) ................................................................................. 70
9.1.7 AM Frequency Shifting (FreqShift) ....................................................................................... 70
9.2 Input Configuration (Address 02h) ................................................................................................. 71
9.2.1 Input Source Selection (ADC/SP) ......................................................................................... 71
9.2.2 ADC High-Pass Filter Enable (EnAnHPF) ............................................................................ 71
9.2.3 Serial Port Sample Rate (SPRate[1:0]) - Read Only ............................................................ 71
9.2.4 Input Serial Port Digital Interface Format (DIF [2:0]) ............................................................ 71
9.3 AUX Port Configuration (Address 03h) .......................................................................................... 72
9.3.1 Enable Aux Serial Port (EnAuxPort) ..................................................................................... 72
9.3.2 Delay & Warning Port Configuration (DlyPortCfg[1:0]) ......................................................... 72
9.3.3 Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ) .................................................. 72
9.3.4 Aux Serial Port Right Channel Data Select (RChDSel[1:0]) ................................................. 72
9.3.5 Aux Serial Port Left Channel Data Select (LChDSel[1:0]) .................................................... 73
9.4 Output Configuration (Address 04h) ............................................................................................. 73
9.4.1 Output Configuration (OutputCfg[1:0]) .................................................................................. 73
9.4.2 PWM Signals Output Data Select (PWMDSel[1:0]) .............................................................. 73
9.4.3 Channel Delay Settings (OutputDly[3:0]) .............................................................................. 73
9.5 Foldback and Ramp Configuration (Address 05h) ......................................................................... 74
9.5.1 Select VP Level (SelectVP) .................................................................................................. 74
9.5.2 Enable Thermal Foldback (EnTherm) ................................................................................... 74
9.5.3 Lock Foldback Adjust (LockAdj) ........................................................................................... 74
9.5.4 Foldback Attack Delay (AttackDly[1:0]) ................................................................................ 75
4
DS726PP3
CS4525
9.5.5 Enable Foldback Floor (EnFloor) .......................................................................................... 75
9.5.6 Ramp Speed (RmpSpd[1:0]) ................................................................................................ 75
9.6 Mixer / Pre-Scale Configuration (Address 06h) ............................................................................. 75
9.6.1 Pre-Scale Attenuation (PreScale[2:0]) .................................................................................. 75
9.6.2 Right Channel Mixer (RChMix[1:0]) ...................................................................................... 76
9.6.3 Left Channel Mixer (LChMix[1:0]) ......................................................................................... 76
9.7 Tone Configuration (Address 07h) ................................................................................................. 76
9.7.1 De-Emphasis Control (DeEmph) .......................................................................................... 76
9.7.2 Adaptive Loudness Compensation Control (Loudness) ....................................................... 76
9.7.3 Digital Signal Processing High-Pass Filter (EnDigHPF) ....................................................... 77
9.7.4 Treble Corner Frequency (TrebFc[1:0]) ................................................................................ 77
9.7.5 Bass Corner Frequency (BassFc[1:0]) ................................................................................. 77
9.7.6 Tone Control Enable (EnToneCtrl) ....................................................................................... 77
9.8 Tone Control (Address 08h) ........................................................................................................... 78
9.8.1 Treble Gain Level (Treb[3:0]) ................................................................................................ 78
9.8.2 Bass Gain Level (Bass[3:0]) ................................................................................................. 78
9.9 2.1 Bass Manager/Parametric EQ Control (Address 09h) ............................................................. 78
9.9.1 Freeze Controls (Freeze) ...................................................................................................... 78
9.9.2 Hi-Z PWM_SIG Outputs (HiZPSig) ....................................................................................... 79
9.9.3 Bass Cross-Over Frequency (BassMgr[2:0]) ........................................................................ 79
9.9.4 Enable Channel B Parametric EQ (EnChBPEq) ................................................................... 79
9.9.5 Enable Channel A Parametric EQ (EnChAPEq) ................................................................... 79
9.10 Volume and 2-Way Cross-Over Configuration (Address 55h) ..................................................... 80
9.10.1 Soft Ramp and Zero Cross Control (SZCMode[1:0]) .......................................................... 80
9.10.2 Enable 50% Duty Cycle for Mute Condition (Mute50/50) ................................................... 80
9.10.3 Auto-Mute (AutoMute) ........................................................................................................ 80
9.10.4 Enable 2-Way Crossover (En2Way) ................................................................................... 81
9.10.5 2-Way Cross-Over Frequency (2WayFreq[2:0]) ................................................................. 81
9.11 Channel A & B: 2-Way Sensitivity Control (Address 56h) ............................................................ 81
9.11.1 Channel A and Channel B Low-Pass Sensitivity Adjust (LowPass[3:0]) ............................ 81
9.11.2 Channel A and Channel B High-Pass Sensitivity Adjust (HighPass[3:0]) ........................... 82
9.12 Master Volume Control (Address 57h) ........................................................................................ 82
9.12.1 Master Volume Control (MVol[7:0]) .................................................................................... 82
9.13 Channel A and B Volume Control (Address 58h & 59h) .............................................................. 83
9.13.1 Channel X Volume Control (ChXVol[7:0]) ........................................................................... 83
9.14 Sub Channel Volume Control (Address 5Ah) .............................................................................. 83
9.14.1 Sub Channel Volume Control (SubVol[7:0]) ....................................................................... 83
9.15 Mute/Invert Control (Address 5Bh) .............................................................................................. 84
9.15.1 ADC Invert Signal Polarity (InvADC) .................................................................................. 84
9.15.2 Invert Channel PWM Signal Polarity (InvChX) ................................................................... 84
9.15.3 Invert Sub PWM Signal Polarity (InvSub) ........................................................................... 84
9.15.4 ADC Channel Mute (MuteADC) .......................................................................................... 84
9.15.5 Independent Channel A & B Mute (MuteChX) .................................................................... 84
9.15.6 Sub Channel Mute (MuteSub) ............................................................................................ 85
9.16 Limiter Configuration 1 (Address 5Ch) ......................................................................................... 85
9.16.1 Maximum Threshold (Max[2:0]) .......................................................................................... 85
9.16.2 Minimum Threshold (Min[2:0]) ............................................................................................ 85
9.16.3 Peak Signal Limit All Channels (LimitAll) ............................................................................ 86
9.16.4 Peak Detect and Limiter Enable (EnLimiter) ....................................................................... 86
9.17 Limiter Configuration 2 (Address 5Dh) ......................................................................................... 87
9.17.1 Limiter Release Rate (RRate[5:0]) ...................................................................................... 87
9.18 Limiter Configuration 3 (Address 5Eh) ......................................................................................... 87
9.18.1 Enable Thermal Limiter (EnThLim) ..................................................................................... 87
9.18.2 Limiter Attack Rate (ARate[5:0]) ......................................................................................... 87
DS726PP3
5
CS4525
9.19 Power Control (Address 5Fh) ...................................................................................................... 88
9.19.1 Automatic Power Stage Retry (AutoRetry) ......................................................................... 88
9.19.2 Enable Over-Current Protection (EnOCProt) ...................................................................... 88
9.19.3 Select VD Level (SelectVD) ................................................................................................ 88
9.19.4 Power Down ADC (PDnADC) ............................................................................................. 88
9.19.5 Power Down PWM Power Output X (PDnOutX) ................................................................. 89
9.19.6 Power Down (PDnAll) ......................................................................................................... 89
9.20 Interrupt (Address 60h) ............................................................................................................... 89
9.20.1 SRC Lock State Transition Interrupt (SRCLock) ................................................................ 90
9.20.2 ADC Overflow Interrupt (ADCOvfl) ..................................................................................... 90
9.20.3 Channel Overflow Interrupt (ChOvfl) .................................................................................. 90
9.20.4 Amplifier Error Interrupt Bit (AmpErr) .................................................................................. 91
9.20.5 Mask for SRC State (SRCLockM) ...................................................................................... 91
9.20.6 Mask for ADC Overflow (ADCOvflM) .................................................................................. 91
9.20.7 Mask for Channel X and Sub Overflow (ChOvflM) ............................................................. 91
9.20.8 Mask for Amplifier Error (AmpErrM) ................................................................................... 92
9.21 Interrupt Status (Address 61h) - Read Only ................................................................................. 92
9.21.1 SRC State Transition (SRCLockSt) .................................................................................... 92
9.21.2 ADC Overflow (ADCOvflSt) ................................................................................................ 92
9.21.3 Sub Overflow (SubOvflSt) ................................................................................................... 92
9.21.4 Channel X Overflow (ChXOvflSt) ........................................................................................ 93
9.21.5 Ramp-Up Cycle Complete (RampDone) ............................................................................ 93
9.22 Amplifier Error Status (Address 62h) - Read Only ....................................................................... 93
9.22.1 Over-Current Detected On Channel X (OverCurrX) ........................................................... 93
9.22.2 External Amplifier State (ExtAmpSt) ................................................................................... 93
9.22.3 Under Voltage / Thermal Error State (UVTE[1:0]) .............................................................. 94
9.23 Device I.D. and Revision (Address 63h) - Read Only .................................................................. 94
9.23.1 Device Identification (DeviceID[4:0]) ................................................................................... 94
9.23.2 Device Revision (RevID[2:0]) .............................................................................................. 94
10. PARAMETER DEFINITIONS .............................................................................................................. 95
11. REFERENCES .................................................................................................................................... 95
12. PACKAGE DIMENSIONS .................................................................................................................. 96
13. THERMAL CHARACTERISTICS ....................................................................................................... 97
13.1 Thermal Flag ................................................................................................................................ 97
14. ORDERING INFORMATION .............................................................................................................. 97
15. REVISION HISTORY .......................................................................................................................... 98
LIST OF FIGURES
Figure 1.Typical Connection Diagram - Software Mode ........................................................................... 13
Figure 2.Typical Connection Diagram - Hardware Mode .......................................................................... 14
Figure 3.Typical System Configuration 1 .................................................................................................. 15
Figure 4.Typical System Configuration 2 .................................................................................................. 15
Figure 5.Typical System Configuration 3 .................................................................................................. 16
Figure 6.Typical System Configuration 4 .................................................................................................. 17
Figure 7.Serial Audio Input Port Timing .................................................................................................... 21
Figure 8.AUX Serial Port Interface Master Mode Timing .......................................................................... 22
Figure 9.SYS_CLK Timing from Reset ..................................................................................................... 23
Figure 10.PWM_SIGX Timing ................................................................................................................... 23
Figure 11.Control Port Timing - I²C ........................................................................................................... 24
Figure 12.Typical SYS_CLK Input Clocking Configuration ....................................................................... 26
Figure 13.Typical Crystal Oscillator Clocking Configuration ..................................................................... 27
Figure 14.Digital Signal Flow .................................................................................................................... 29
Figure 15.De-Emphasis Filter ................................................................................................................... 31
6
DS726PP3
CS4525
Figure 16.Bi-Quad Filter Architecture ........................................................................................................ 33
Figure 17.Peak Signal Detection & Limiting .............................................................................................. 37
Figure 18.Foldback Process ..................................................................................................................... 40
Figure 19.Popguard Connection Diagram ................................................................................................. 46
Figure 20.2-Channel Full-Bridge PWM Output Delay ............................................................................... 50
Figure 21.3-Channel PWM Output Delay .................................................................................................. 50
Figure 22.Typical SYS_CLK Input Clocking Configuration ....................................................................... 54
Figure 23.Hardware Mode PWM Output Delay ......................................................................................... 55
Figure 24.Hardware Mode Digital Signal Flow .......................................................................................... 56
Figure 25.Foldback Process ..................................................................................................................... 57
Figure 26.Output Filter - Half-Bridge ......................................................................................................... 59
Figure 27.Output Filter - Full-Bridge .......................................................................................................... 60
Figure 28.Recommended Unity Gain Input Filter ...................................................................................... 61
Figure 29.Recommended 2 VRMS Input Filter ........................................................................................... 61
Figure 30.I²S Serial Audio Formats ........................................................................................................... 62
Figure 31.Left-Justified Serial Audio Formats ........................................................................................... 62
Figure 32.Right-Justified Serial Audio Formats ......................................................................................... 63
Figure 33.Control Port Timing, I²C Write ................................................................................................... 64
Figure 34.Control Port Timing, I²C Read ................................................................................................... 64
LIST OF TABLES
Table 1. I/O Power Rails ........................................................................................................................... 12
Table 2. Bass Shelving Filter Corner Frequencies .................................................................................... 31
Table 3. Treble Shelving Filter Corner Frequencies ................................................................................. 32
Table 4. Bass Management Cross-Over Frequencies .............................................................................. 35
Table 5. 2-Way Cross-Over Frequencies .................................................................................................. 42
Table 6. Auxiliary Serial Port Data Output ................................................................................................ 43
Table 7. Nominal Switching Frequencies of the Auxiliary Serial Output ................................................... 43
Table 8. PWM Power Output Configurations ............................................................................................ 45
Table 9. Typical Ramp Times for Various VP Voltages ............................................................................ 46
Table 10. PWM Logic-Level Output Configurations .................................................................................. 49
Table 11. PWM Output Switching Rates and Quantization Levels ........................................................... 51
Table 12. Output of PWM_SIG Outputs .................................................................................................... 52
Table 13. SYS_CLK Frequency Selection ................................................................................................ 54
Table 14. Input Source Selection .............................................................................................................. 55
Table 15. Serial Audio Interface Format Selection .................................................................................... 55
Table 16. Thermal Foldback Enable Selection ......................................................................................... 57
Table 17. PWM Output Switching Rates and Quantization Levels ........................................................... 58
Table 18. Low-Pass Filter Components - Half-Bridge ............................................................................... 59
Table 19. DC-Blocking Capacitors Values - Half-Bridge ........................................................................... 59
Table 20. Low-Pass Filter Components - Full-Bridge ............................................................................... 60
Table 21. Power Supply Configuration and Settings ................................................................................. 63
DS726PP3
7
CS4525
XTI
XTO
SYS_CLK
AUX_LRCK/AD0
AUX_SCLK
AUX_SDOUT
DLY_SDIN/EX_TWR
DLY_SDOUT
PWM_SIG1
PWM_SIG2
PGND
PGND
1. PIN DESCRIPTIONS - SOFTWARE MODE
48
47
46
45
44
43
42
41
40
39
38
37
INT
1
36
VP
SCL
2
35
OUT1
SDA
3
34
PGND
LRCK
4
33
PGND
SCLK
5
32
OUT2
SDIN
6
31
VP
HP_DETECT/MUTE
7
30
VP
RST
8
29
OUT3
LVD
9
28
PGND
DGND
10
27
PGND
VD_REG
11
26
OUT4
VD
12
25
VP
Pin Name
Pin #
Thermal Pad
18
19
AGND
FILT+
VQ
AFILTL
AFILTR
AINL
20
21
22
23
24
RAMP_CAP
17
PGND
16
PGND
15
OCREF
14
AINR
13
VA_REG
Top-Down (Through Package) View
48-Pin QFN Package
Pin Description
INT
1
Interrupt (Output) - Indicates an interrupt condition has occurred.
SCL
2
Serial Control Port Clock (Input) - Serial clock for the I²C control port.
SDA
3
Serial Control Data (Input/Output) - Bi-directional data I/O for the I²C control port.
LRCK
4
Left Right Clock (Input) - Determines which channel, Left or Right, is currently active on the serial
audio data line.
SCLK
5
Serial Clock (Input) - Serial bit clock for the serial audio interface.
SDIN
6
Serial Audio Data Input (Input) - Input for two’s complement serial audio data.
HP_DETECT/
MUTE
7
Headphone Detect / Mute (Input) - Headphone detection or mute input signal as configured via the
I²C control port.
RST
8
Reset (Input) - The device enters a low power mode and all internal registers are reset to their
default settings when this pin is driven low.
8
DS726PP3
CS4525
LVD
9
VD Voltage Level Indicator (Input) - Identifies the voltage level attached to VD. When applying
5.0 V to VD, LVD must be connected to VD. When applying 2.5 V or 3.3 V to VD, LVD must be
DGND.
DGND
10
Digital Ground (Input) - Ground for the internal logic and digital I/O.
VD_REG
11
Core Logic Power (Output) - Internally generated low voltage power supply for digital logic.
VD
12
Power (Input) - Positive power supply for the internal regulators and digital I/O.
VA_REG
13
Analog Power (Output) - Internally generated positive power for the analog section and I/O.
AGND
14
Analog Ground (Input) - Ground reference for the internal analog section and I/O.
FILT+
15
Positive Voltage Reference (Output) - Positive reference voltage for the internal ADC sampling
circuits.
VQ
16
Common Mode Voltage (Output) - Filter connection for internal common mode voltage.
AFILTL
AFILTR
17
18
Antialias Filter Connection (Output) - Antialias filter connection for ADC inputs.
AINL
AINR
19
20
Analog Input (Input) - The full-scale input level is specified in the ADC Analog Characteristics
specification table.
OCREF
21
Over Current Reference Setting (Input) - Sets the reference for over current detection.
PGND
RAMP_CAP
VP
22,23
27,28
Power Ground (Input) - Ground for the individual output power half-bridge devices.
33,34
37,38
24
Output Ramp Capacitor (Input) - Used by the PWM Popguard Transient Control to suppress the
initial pop in half-bridge-configured outputs.
25,30,
High Voltage Power (Input) - High voltage power supply for the individual half-bridge devices.
31,36
OUT4
OUT3
OUT2
OUT1
26
29
32
35
PWM Output (Output) - Amplified PWM power outputs.
PWM_SIG2
PWM_SIG1
39
40
Logic Level PWM Output (Output) - Logic Level PWM switching signals.
DLY_SDOUT
41
Delay Serial Audio Data Out (Output) - Output for two’s complement serial audio data.
DLY_SDIN/
EX_TWR
42
Delay Serial Audio Data Input (Input) - Input for two’s complement serial audio data.
External Thermal Warning (Input) - Input for an external thermal warning signal. Configurable via
the I²C control port.
AUX_SDOUT
43
Auxiliary Port Serial Audio Data Out (Output) - Output for two’s complement auxiliary port serial
data.
AUX_SCLK
44
Auxiliary Port Serial Clock (Output) - Serial clock for the auxiliary port serial interface.
AUX_LRCK/
AD0
45
Auxiliary Port Left Right Clock (Output) - Determines which channel, Left or Right, is currently
active on the serial audio data line.
AD0 (Input) - Sets the LSB of the I²C device address. Sensed on the release of RST.
SYS_CLK
46
System Clock (Input/Output) -Clock source for the internal logic, processing, and modulators. This
pin should be connected to through a 10kΩ to ground when unused.
XTO
47
Crystal Oscillator Output (Output) - Crystal oscillator driver output.
XTI
48
Crystal Oscillator Input (Input) - Crystal oscillator driver input.
Thermal Pad
DS726PP3
-
Thermal Pad - Thermal relief pad for optimized heat dissipation. See “QFN Thermal Pad” on
page 65 for more information.
9
CS4525
Pin Name
TSTI
TSTO
SYS_CLK
I2S/LJ
EN_TFB
ERROC
ERRUVTE
TWR
TSTO
TSTO
PGND
PGND
2. PIN DESCRIPTIONS - HARDWARE MODE
48
47
46
45
44
43
42
41
40
39
38
37
CLK_FREQ0
1
36
VP
CLK_FREQ1
2
35
OUT1
ADC/SP
3
34
PGND
LRCK
4
33
PGND
SCLK
5
32
OUT2
SDIN
6
31
VP
MUTE
7
30
VP
RST
8
29
OUT3
LVD
9
28
PGND
DGND
10
27
PGND
VD_REG
11
26
OUT4
VD
12
25
VP
Pin #
Thermal Pad
18
19
AGND
FILT+
VQ
AFILTL
AFILTR
AINL
20
21
22
23
24
RAMP_CAP
17
PGND
16
PGND
15
OCREF
14
AINR
13
VA_REG
Top-Down (Through Package) View
48-Pin QFN Package
Pin Description
CLK_FREQ0
CLK_FREQ1
1
2
Clock Frequency (Input) - Determines the frequency of the clock expected to be driven into the
SYS_CLK pin. CLK_FREQ1 must be connected to DGND.
ADC/SP
3
ADC/Serial Port (Input) - Selects between the Analog to Digital Converter and the Serial Port for
audio input. Selects the ADC when high or the serial port when low.
LRCK
4
Left Right Clock (Input) - Determines which channel, Left or Right, is currently active on the serial
audio data line.
SCLK
5
Serial Clock (Input) - Serial bit clock for the serial audio interface.
SDIN
6
Serial Audio Data Input (Input) - Input for two’s complement serial audio data.
MUTE
7
Mute (Input) - The PWM outputs will output silence as a 50% duty cycle signal when this pin is
driven low.
RST
8
Reset (Input) - The device enters a low power mode and all internal registers are reset to their
default settings when this pin is driven low.
10
DS726PP3
CS4525
LVD
9
VD Voltage Level Indicator (Input) - Identifies the voltage level attached to VD. When applying
5.0 V to VD, LVD must be connected to VD. When applying 2.5 V or 3.3 V to VD, LVD must be connected to DGND.
DGND
10
Digital Ground (Input) - Ground for the internal logic and I/O.
VD_REG
11
Core Logic Power (Output) - Internally generated low voltage power supply for digital logic.
VD
12
Digital Power (Input) - Positive power supply for the internal regulators and digital I/O.
VA_REG
13
Analog Power (Output) - Internally generated positive power for the analog section and I/O.
AGND
14
Analog Ground (Input) - Ground reference for the internal analog section and I/O.
FILT+
15
Positive Voltage Reference (Output) - Positive reference voltage for the internal ADC sampling
circuits.
VQ
16
Common Mode Voltage (Output) - Filter connection for internal common mode voltage.
AFILTL
AFILTR
17
18
Antialias Filter Connection (Output) - Antialias filter connection for ADC inputs.
AINL
AINR
19
20
Analog Input (Input) - The full-scale input level is specified in the ADC Analog Characteristics
specification table.
OCREF
21
Over Current Reference Setting (Input) - Sets the reference for over current detection.
PGND
RAMP_CAP
VP
22,23
27,28
Power Ground (Input) - Ground for the individual output power half-bridge devices.
33,34
37,38
24
Output Ramp Capacitor (Input) - This pin should be connected directly to VP in hardware mode.
25,30,
High Voltage Power (Input) - High voltage power supply for the individual half-bridge devices.
31,36
OUT4
OUT3
OUT2
OUT1
26
29
32
35
PWM Output (Output) - Amplified PWM power outputs.
TSTO
39
40
Test Output (Output) - These pins are outputs used for the Logic Level PWM switching signals
available only in software mode. They must be left unconnected for hardware mode operation.
TWR
41
Thermal Warning Output (Output) - Thermal warning output.
ERRUVTE
42
Thermal and Undervoltage Error Output (Output) - Error flag for thermal shutdown and undervoltage.
ERROC
43
Overcurrent Error Output (Output) - Overcurrent error flag.
EN_TFB
44
Enable Thermal Feedback (Input) - Enables the thermal foldback feature when high.
I2S/LJ
45
I²S/Left Justified (Input) - Selects between I²S and Left-Justified data format for the serial input
port. Selects I²S when high and LJ when low.
SYS_CLK
46
System Clock (Input/Output) -Clock source for the delta-sigma modulators.
TSTO
47
Test Output (Output) - This pin is an output used for the crystal oscillator driver available only in
software mode. It must be left unconnected for normal hardware mode operation.
TSTI
48
Test Input (Input) - This pin is an input used for the crystal oscillator driver available only in software mode. It must be tied to digital ground for normal hardware mode operation.
Thermal Pad
DS726PP3
-
Thermal Pad - Thermal relief pad for optimized heat dissipation. See “QFN Thermal Pad” on
page 65 for more information.
11
CS4525
2.1
Digital I/O Pin Characteristics
The logic level for each input is set by its corresponding power supply and should not exceed the maximum ratings.
Power
Pin
Supply Number
Software Mode
VD
Pin Name
I/O
Driver
Receiver
INT
SCL
SDA
HP_DETECT
MUTE
DLY_SDOUT
DLY_SDIN
EX_TWR
AUX_SDOUT
AUX_SCLK
AUX_LRCK
PWM_SIG2
PWM_SIG1
Output
Input
Input/Output
Input
Input
Output
Input
Input
Output
Output
Output
Output
Output
2.5 V-5.0 V, Open Drain
2.5 V-5.0 V, Open Drain
2.5 V-5.0 V, CMOS
2.5 V-5.0 V, CMOS
2.5 V-5.0 V, CMOS
2.5 V-5.0 V, CMOS
2.5 V, CMOS
2.5 V, CMOS
2.5 V-5.0 V, with Hysteresis
2.5 V-5.0 V, with Hysteresis
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
-
1
2
3
7
41
42
43
44
45
CLK_FREQ0
CLK_FREQ1
ADC/SP
MUTE
TWR
ERRUVTE
ERROC
EN_TFB
I²S/LJ
Input
Input
Input
Input
Output
Output
Output
Input
Input
2.5 V-5.0 V, Open Drain
2.5 V-5.0 V, Open Drain
2.5 V-5.0 V, Open Drain
-
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
4
5
6
8
9
46
26
29
32
35
LRCK
SCLK
SDIN
RST
LVD
SYS_CLK
OUT4
OUT3
OUT2
OUT1
Input
Input
Input
Input
Input
Input/Output
Output
Output
Output
Output
2.5 V-5.0 V, CMOS
8.0 V-18.0 V Power MOSFET
8.0 V-18.0 V Power MOSFET
8.0 V-18.0 V Power MOSFET
8.0 V-18.0 V Power MOSFET
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
2.5 V-5.0 V
-
1
2
3
7
41
42
VD_REG
43
44
45
39
40
Hardware Mode
VD
All Modes
VD
VP
Table 1. I/O Power Rails
12
DS726PP3
CS4525
3. TYPICAL CONNECTION DIAGRAMS
+8 V to +18 V
+3.3 or +5 V
470 µF
Analog
Audio
Inputs
25
30
31
VP
0.1 µF
VP
0.1 µF
VP
VD
12
0.1 µF
0.1 µF
470 µF
36
VP
10 µF 0.1 µF
RAMP_CAP 35
Analog
Audio
Switch
19
AINL
20
AINR
OUT1 35
Analog
Monitor
Output
OUT2 32
Output
Filter
CS4525
Crystal
48
XTI
24.576 MHz
47
XTO
MPEG
Audio
Processor
46
SYS_CLK
OUT3 29
- or -
22 kΩ
HDMI
Receiver
OUT4 26
5
SCLK
4
LRCK
6
SDIN
7
HP_DETECT/MUTE
Line
Output
PWM_SIG1 40
Lip-Synch
Delay
43
AUX_SDOUT
45
AUX_LRCK/AD0
44
AUX_SCLK
41
DLY_SDOUT
42
DLY_SDIN
NJU26902
- or -
22 kΩ†
LVD
+2.5V
0.1 µF
11
Headphone
Output
PWM_SIG2 39
VD or GND
9
OCREF 21
10 µF
Output
Filter
16.2 kΩ
VD_REG
FILT+ 15
VA_REG 13
0.1 µF
10 µF
10 µF
150 pF
150 pF
1 µF
3
SDA
1
INT
8
RST
AFILTA 17
AFILTB 18
PG
N
D
PG
N
D
PG
N
D
PG
N
D
PG
N
D
PG
N
D
D
PG
N
10
D
VQ 16
PG
N
† Note: On release of RST, AD0 is read as input on the
SCL
D
*Note: Resistors are required for I²C control port
operation.
2
D
G
N
MicroController
AGND 14
2 kΩ*
2 kΩ*
22 kΩ
VD
22
23
27
28
33
34
37
38
AUX_LRCK line.
Figure 1. Typical Connection Diagram - Software Mode
DS726PP3
13
CS4525
+8 V to +18 V
+3.3 or +5 V
470 µF
Analog
Audio
Inputs
25
30
31
VP
0.1 µF
VP
0.1 µF
VP
VD
12
0.1 µF
0.1 µF
470 µF
36
VP
10 µF 0.1 µF
RAMP_CAP 35
Analog
Audio
Switch
19
AINL
20
AINR
OUT1 35
OUT2 32
Analog
Monitor
Output
Output
Filter
CS4525
Audio
Processor
Clock
24.576 MHz
5
SCLK
4
LRCK
OUT3 29
OUT4 26
6
SDIN
46
SYS_CLK
1
CLK_FREQ0
2
CLK_FREQ1
TSTO 40
TSTO 39
22 kΩ
22 kΩ
22 kΩ
VD
MicroController
Output
Filter
41
TWR
42
ERRUVTE
43
ERROC
44
EN_TFB
45
I²S/LJ
3
ADC/SP
7
MUTE
8
RST
47
TSTO
48
TSTI
11
VD_REG
LVD
VD or GND
9
OCREF 21
16.2 kΩ
FILT+ 15
VA_REG 13
0.1 µF
10 µF
10 µF
150 pF
150 pF
1 µF
AGND 14
AFILTA 17
AFILTB 18
VQ 16
PG
N
PG
N
D
D
PG
D
PG
23
27
28
33
34
37
38
N
N
PG
D
D
PG
N
22
N
PG
N
D
D
PG
N
N
D
G
10
D
0.1 µF
D
10 µF
Figure 2. Typical Connection Diagram - Hardware Mode
14
DS726PP3
CS4525
4. TYPICAL SYSTEM CONFIGURATION DIAGRAMS
2 x 7 W Stereo + 1 x 15 W Subwoofer
Main Tuner
Monitor Out
CS4525
PIP Tuner
Analog In
A/V In 1
Digital In
Digital Out
Control
Port
Control Port
A/V In 2
A/V Switch
Audio
Delay
MPEG
Decoder
Aux
Out
Clock
Out
27 MHz
A/V In X
Delay
Port
Gate
Drive
Left
Speaker
Gate
Drive
Right
Speaker
Gate
Drive
Subwoofer
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
Crystal In
Crystal Out
HP/
Line
Out
Figure 3. Typical System Configuration 1
2 x 15 W Stereo + 1 x 30 W Subwoofer
Main Tuner
Monitor Out
Analog
Out
PIP Tuner
Sound
Processor
A/V In 1
A/V In 2
Var/Fixed Out
CS4525
Analog In
Analog
In
A/V Switch
Digital In
Control
Port
Control
Port
Audio
Delay
A/V In X
27 MHz
Aux
Out
Crystal In
Crystal Out
Delay
Port
Clock
Out
Gate
Drive
Left
Speaker
Gate
Drive
Gate
Drive
Right
Speaker
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
Analog
Out
CS4412A
22 kΩ
PWM In
Gate
Drive
Gate
Drive
Subwoofer
Gate
Drive
Status
Out
Gate
Drive
Figure 4. Typical System Configuration 2
DS726PP3
15
CS4525
2 x 30 W Stereo + 1 x 30 W Subwoofer
Main Tuner
Monitor Out
Analog
Out
PIP Tuner
Sound
Processor
A/V In 1
A/V In 2
Var/Fixed Out
CS4525
Analog In
Analog
In
A/V Switch
Digital In
Control
Port
Control
Port
Audio
Delay
A/V In X
18.432 MHz
Aux
Out
Crystal In
Crystal Out
Delay
Port
Clock
Out
Gate
Drive
Gate
Drive
Left
Speaker
Gate
Drive
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
Analog
Out
CS4412A
Gate
Drive
22 kΩ
PWM In
Gate
Drive
Right
Speaker
Gate
Drive
Status
Out
Gate
Drive
CS4412A
22 kΩ
PWM In
Gate
Drive
Gate
Drive
Subwoofer
Gate
Drive
Status
Out
Gate
Drive
Figure 5. Typical System Configuration 3
16
DS726PP3
CS4525
2 x 15 W Bi-Amp Stereo with Subwoofer Output
Main Tuner
Monitor Out
Analog
Out
PIP Tuner
A/V In 1
A/V In 2
Var/Fixed Out
Sound
Processor
Analog
In
A/V Switch
CS4525
Analog In
Digital
Out
Control
Port
Digital In
Control
Port
Audio
Delay
A/V In X
18.432 MHz
Aux
Out
Crystal In
Crystal Out
Analog
Out
Delay
Port
Clock
Out
Gate
Drive
Left
Tweeter
Gate
Drive
Gate
Drive
Left
Woofer
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
Sub
Out
CS4525
Analog In
Digital In
Control
Port
Delay
Port
Aux
Out
Gate
Drive
Right
Tweeter
Gate
Drive
Gate
Drive
Right
Woofer
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
Figure 6. Typical System Configuration 4
DS726PP3
17
CS4525
5. CHARACTERISTICS AND SPECIFICATIONS
RECOMMENDED OPERATING CONDITIONS
AGND = DGND = PGND = 0 V; all voltages with respect to ground.
Parameters
Symbol
Min
Nom
Max
Units
VD
2.375
2.5
2.625
V
VD
3.135
3.3
3.465
V
VD
4.75
5.0
5.25
V
VP
8.0
-
18.0
V
Ambient Temperature
TA
0
-
+70
°C
Junction Temperature
TJ
0
-
+125
°C
DC Power Supply
Digital and Analog Core
(Note 1)
Amplifier Outputs
Temperature
Notes:
1. For VD = 2.5 V, VA_REG and VD_REG must be connected to VD. See section 6.7 on page 63 for
details.
ABSOLUTE MAXIMUM RATINGS
AGND = DGND = PGND = 0 V; all voltages with respect to ground.
Parameters
Symbol
Min
Max
Units
VP
VP
VD
-0.3
-0.3
-0.3
19.8
23.0
6.0
V
V
V
DC Power Supply
Power Stage
Power Stage
Digital and Analog Core
Outputs Switching and Under Load
No Output Switching
Inputs
Input Current
(Note 2)
Iin
-
±10
mA
Analog Input Voltage
(Note 3)
VINA
AGND - 0.7
VA_REG + 0.7
V
Digital Input Voltage
(Note 3)
VIND
-0.3
VD + 0.4
V
TA
-20
+85
°C
Tstg
-65
+150
°C
Temperature
Ambient Operating Temperature - Power Applied
Commercial
Storage Temperature
WARNING: Operation at conditions beyond the Recommended Operating Conditions may affect device reliability,
and functional operation beyond Recommended Operating Conditions is not implied.
Notes:
2. Any pin except supplies. Transient currents of up to ±100 mA on the analog input pins will not cause
SCR latch-up.
3. The maximum over/under voltage is limited by the input current.
18
DS726PP3
CS4525
ANALOG INPUT CHARACTERISTICS
Test Conditions (unless otherwise specified): AGND = DGND = PGND = 0 V; All voltages with respect to ground;
TA = 25°C; VD = 3.3 V; Input Signal: 1 kHz sine wave through the recommended passive input filter shown in Figure 28 on page 61; Capacitor values connected to AFILTA, AFILTB, FILT+, VQ, VD_REG, and VA_REG as shown
in Figure 1 on page 13; Sample Frequency = 48 kHz; 10 Hz to 20 kHz Measurement Bandwidth; Power outputs in
power-down state (PDnOut1 = 1, PDnOut2 = 1, PDnOut3/4 = 1).
Parameter
Dynamic Range (Note 4)
A-weighted
unweighted
-1 dB
-20 dB
-60 dB
Total Harmonic Distortion + Noise
DC Accuracy
Interchannel Gain Mismatch
Gain Drift
Interchannel Isolation
Full-scale Input Voltage
VD = 2.5V (Note 5)
VD = 3.3V
VD = 5.0V
(Note 6)
Input Impedance
Notes:
Min
Typ
Max
Unit
90
87
-
95
92
-86
-72
-32
-77
-
dB
dB
dB
dB
dB
0.786*VD
0.590*VD
0.398*VD
40
0.05
±100
90
0.827*VD
0.621*VD
0.419*VD
-
0.868*VD
0.652*VD
0.440*VD
-
dB
ppm/°C
dB
Vpp
Vpp
Vpp
kΩ
4. Referred to the typical full-scale voltage
5. For VD = 2.5 V, VA_REG and VD_REG must be connected to VD. See section 6.7 on page 63 for
details.
6. Measured between AINx and AGND.
ADC DIGITAL FILTER CHARACTERISTICS
Parameter
Passband (Frequency Response) (Note 7)
to -0.1 dB corner
Passband Ripple
Stopband
Min
Typ
Max
0
-
0.4948
Fs
-0.09
-
0
dB
(Note 7) 0.6677
Unit
-
-
Fs
48.4
-
-
dB
-
2.7/Fs
-
s
-3.0 dB
-0.13 dB
-
3.7
24.2
-
Hz
Hz
20 Hz
-
10
-
Deg
Stopband Attenuation
Total Group Delay
High-Pass Filter Characteristics
Frequency Response
Phase Deviation
Passband Ripple
-
-
0.17
dB
Filter Settling Time
-
105/Fs
-
s
Notes:
7. Filter response is clock dependent and scales with the ADC sampling frequency (Fs). With a
27.000 MHz or 24.576 MHz XTAL/SYS_CLK, Fs is equal to the applied clock divided by 512. With an
18.432 MHz XTAL/SYS_CLK, Fs is equal to the applied clock divided by 384.
DS726PP3
19
CS4525
PWM POWER OUTPUT CHARACTERISTICS
Test Conditions (unless otherwise specified): AGND = DGND = PGND = 0 V; All voltages with respect to ground;
TA = 25°C; VD = 3.3 V; VP = 18 V; RL = 8 Ω for full-bridge, RL = 4 Ω for half-bridge and parallel full-bridge;
OutputDly[3:0] = 1111; PhaseShift = 1 for half-bridge, PhaseShift = 0 for full-bridge and parallel full-bridge;
Input Signal: full-scale 997 Hz sine wave through serial audio input port, 48 kHz sample rate; Capacitor values
connected to AFILTA, AFILTB, FILT+, VQ, VD_REG, and VA_REG as shown in Figure 1 on page 13; PWM Switch
Rate = 384 kHz; 10 Hz to 20 kHz Measurement Bandwidth; Performance measurements taken through AES17 filter.
Parameters
Symbol
Conditions
Min
Typ
Max
Units
THD+N < 10%
THD+N < 1%
THD+N < 10%
THD+N < 1%
THD+N < 10%
THD+N < 1%
-
15
12
7
5.5
30
23.5
-
W
W
W
W
W
W
PO = 1 W
PO = 0 dBFS = 11.3 W
PO = 1 W
PO = 0 dBFS = 5.0 W
PO = 1 W
PO = 0 dBFS = 22.6 W
-
0.05
0.10
0.12
0.28
0.1
0.3
-
%
%
%
%
%
%
PO = -60 dBFS, A-Weighted
PO = -60 dBFS, Unweighted
PO = -60 dBFS, A-Weighted
PO = -60 dBFS, Unweighted
PO = -60 dBFS, A-Weighted
PO = -60 dBFS, Unweighted
-
102
99
99
96
102
99
-
dB
dB
dB
dB
dB
dB
RDS(ON)
Id = 0.5 A, TJ = 50°C
-
280
-
mΩ
h
PO = 2 x 15 W, RL = 8 Ω
-
85
-
%
Power Output per Channel
Stereo Full-Bridge
Half-Bridge
PO
Parallel Full-Bridge
Total Harmonic Distortion + Noise
Stereo Full-Bridge
Half-Bridge
THD+N
Parallel Full-Bridge
Dynamic Range
Stereo Full-Bridge
Half-Bridge
DYR
Parallel Full-Bridge
MOSFET On Resistance
Efficiency
Minimum Output Pulse Width
PWmin
No Load
-
50
-
ns
Rise Time of OUTx
tr
Resistive Load
-
20
-
ns
Fall Time of OUTx
tf
Resistive Load
-
20
-
ns
ICE
TA = 25°C, OCREF = 16.2 kΩ
TA = 25°C, OCREF = 18 kΩ
TA = 25°C, OCREF = 22 kΩ
-
2.5
2.1
1.7
-
A
A
A
-
105
-
°C
PWM Output Over-Current Error Trigger Point
Junction Thermal Warning Trigger Point
TTW
-
125
-
°C
VP Under-Voltage Error Falling Trigger Point
VUVFALL
TA = 25°C
-
4.7
4.9
V
VP Under-Voltage Error Rising Trigger Point
VUVRISE
TA = 25°C
-
4.95
5.4
V
Junction Thermal Error Trigger Point
20
TTE
DS726PP3
CS4525
SERIAL AUDIO INPUT PORT SWITCHING SPECIFICATIONS
AGND = DGND = PGND = 0 V; TA = 25°C; VD = 3.3 V; Inputs: Logic 0 = DGND; Logic 1 = VD.
Parameters
Symbol
Min
Nominal
Max
Units
FSI
28.5
39.5
39.5
86.4
32
44.1
48
96
35.2
52.8
52.8
105.6
kHz
kHz
kHz
kHz
45
-
55
%
1/tp
FSI*2*Nbits
-
FCLK/3
Hz
45
-
55
%
LRCK Setup Time Before SCLK Rising Edge
ts(LK-SK)
40
-
-
ns
SDIN Setup Time Before SCLK Rising Edge
ts(SD-SK)
25
-
-
ns
th
10
-
-
ns
1
-
-
ms
Supported Input Sample Rates
LRCK Duty Cycle
SCLK Frequency
(Note 8),(Note 9)
SCLK Duty Cycle
SDIN Hold Time After SCLK Rising Edge
RST pin Low Pulse Width
Notes:
(Note 10)
8. FCLK is the frequency of the crystal connected to the XTI/XTO pins or the input SYS_CLK signal.
9. Nbits is the number of bits per sample of the serial digital input.
10. After powering up the CS4525, RST should be held low until the power supplies and clocks are stable.
//
LRCK
//
ts(LK-SK)
//
SCLK
tr
ts(SD-SK)
SDIN
tP
//
MSB
//
tf
//
th
MSB-1
Figure 7. Serial Audio Input Port Timing
DS726PP3
21
CS4525
AUX SERIAL AUDIO I/O PORT SWITCHING SPECIFICATIONS
AGND = DGND = PGND = 0 V; TA = 25°C; VD = 3.3 V; AUX_SDOUT & DLY_SDOUT CL = 15 pF; Inputs:
Logic 0 = DGND; Logic 1 = VD; (Note 11).
Parameters
Symbol
Min
Typ
Max
Units
FSO
-
FCLK/384
FCLK/512
FCLK/512
-
Hz
Hz
Hz
-
50
-
%
Input Source: Analog Inputs (Internal ADC)
Output Sample Rate
(Note 16)
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
AUX_LRCK Duty Cycle
AUX_LRCK Period
-
1/FSO
-
s
-
48*FSO
64*FSO
64*FSO
-
Hz
Hz
Hz
AUX_SCLK Duty Cycle
-
50
-
%
AUX_SCLK Period
-
1/FSCLKO
-
s
-
FSI
FSI/2
-
Hz
Hz
45
-
55
%
TSI - TCLK
TSI
TSI + TCLK
s
-
FSCLKI
FSCLKI/2
-
Hz
Hz
30
-
70
%
TSCLKI - TCLK
2*TSCLKI - TCLK
TSCLKI
2*TSCLKI
TSCLKI + TCLK
2*TSCLKI + TCLK
s
s
-
-
20
ns
AUX_SCLK Frequency
(Note 16)
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’ FSCLKO
ClkFreq[1:0] = ‘10’
Input Source: Serial Audio Input Port
Output Sample Rate
FS-In = 32kHz, 44.1 kHz, 48 kHz
FS-In = 96 kHz
AUX_LRCK Duty Cycle
(Note 13)
AUX_LRCK Period
AUX_SCLK Frequency
(Note 14)
FSO
(Note 12, 13)
FS-In = 32kHz, 44.1 kHz, 48 kHz
FS-In = 96 kHz
AUX_SCLK Duty Cycle
AUX_SCLK Period
(Note 13, 14)
FS-In = 32kHz, 44.1 kHz, 48 kHz
FS-In = 96 kHz
Input Source: Analog Inputs or Serial Audio Input Port
AUX_LRCK Rising Edge to AUX_SCLK Falling Edge
tLTSF
AUX_SCLK Rising Edge to Data Output Valid
tSRDV
-
-
TCLK + 20
ns
DLY_SDIN Setup Time Before AUX_SCLK Rising Edge
tDIS
25
-
-
ns
DLY_SDIN Hold Time After AUX_SCLK Rising Edge
tDIH
10
-
-
ns
Notes:
11. FCLK is the frequency of the crystal connected to the XTI/XTO pins or the input SYS_CLK signal.
TCLK = 1/FCLK.
12. FSI is the frequency of the input LRCK signal. TSI = 1/FSI
13. May vary during normal operation.
14. FSCLKI is the frequency of the input SCLK signal. TSCLKI = 1/FSCLKI.
AUX_LRCK
AUX_SCLK
tLTSF
tSRDV
AUX_SDOUT
DLY_SDOUT
LSB
DLY_SDIN
LSB
MSB
tDISU
MSB - 1
tDIH
MSB
MSB - 1
Figure 8. AUX Serial Port Interface Master Mode Timing
22
DS726PP3
CS4525
XTI SWITCHING SPECIFICATIONS
Parameter
External Crystal Operating Frequency
(Notes 15, 16)
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
Symbol
Min
Typ
Max
Unit
FCLK
18.240
24.330
26.730
18.432
24.576
27.000
18.617
24.822
27.270
MHz
MHz
MHz
45
50
55
%
XTI Duty Cycle
Notes:
15. External crystal oscillator mode only available in Software Mode.
SYS_CLK SWITCHING SPECIFICATIONS
AGND = DGND = PGND = 0 V; TA = 25°C; VD = 3.3 V; Input: Logic 0 = DGND; Logic 1 = VD, SYS_CLK Output:
CL = 20 pF.
Parameter
Symbol
Min
Typ
Max
Unit
FCLK
18.240
24.330
26.730
18.432
24.576
27.000
18.617
24.822
27.270
MHz
MHz
MHz
Rising Edge RST to start of SYS_CLK
tsclko
-
1024*tsclki
-
SYS_CLK Period
tsclki
37.04
-
54.25
ns
45
50
55
%
External Clock Operating Frequency
(Note 16)
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
SYS_CLK Duty Cycle
SYS_CLK high time
tclkih
16.67
-
29.84
ns
SYS_CLK low time
tclkil
16.67
-
29.84
ns
Notes:
16. ClkFreq[1:0] = ‘10’ mode only in Software Mode. See “Clock Frequency (ClkFreq[1:0])” on page 69
for software mode configuration settings. See “System Clocking” on page 54 for hardware mode
configuration settings.
SYS_CLK
(output)
tsclko
___
RST
Figure 9. SYS_CLK Timing from Reset
PWM_SIGX SWITCHING SPECIFICATIONS
AGND = DGND = PGND = 0 V; TA = 25°C; VD = 3.3 V; Load = 10 pF.
Parameter
Symbol
Min
Typ
Max
Unit
Rise Time of PWM_SIGx
tr
-
2.1
-
ns
Fall Time of PWM_SIGx
tf
-
1.4
-
ns
tr
tf
PWM_SIGx
Figure 10. PWM_SIGX Timing
DS726PP3
23
CS4525
I²C CONTROL PORT SWITCHING SPECIFICATIONS
AGND = DGND = PGND = 0 V; TA = 25°C; VD = 3.3 V; Inputs: Logic 0 = DGND; Logic 1 = VD; SDA CL = 30 pF.
Symbol
Min
Max
Unit
SCL Clock Frequency
Parameter
fscl
-
100
kHz
RST Rising Edge to Start
tirs
500
-
ns
Bus Free Time Between Transmissions
tbuf
4.7
-
µs
Start Condition Hold Time (prior to first clock pulse)
thdst
4.0
-
µs
Clock Low time
tlow
4.7
-
µs
Clock High Time
thigh
4.0
-
µs
Setup Time for Repeated Start Condition
tsust
4.7
-
µs
thdd
10
-
ns
tsud
250
-
ns
Rise Time of SCL and SDA
trc
-
1
µs
Fall Time SCL and SDA
tfc
-
300
ns
SDA Hold Time from SCL Falling
(Note 17)
SDA Setup time to SCL Rising
Setup Time for Stop Condition
tsusp
4.7
-
µs
Acknowledge Delay from SCL Falling
tack
300
1000
ns
Notes:
17. Data must be held for sufficient time to bridge the transition time, tfc, of SCL.
RST
t irs
Stop
Repeated
Start
Start
Stop
SDA
t buf
t
t high
t hdst
tf
hdst
t susp
SCL
t
low
t
hdd
t sud
t sust
tr
Figure 11. Control Port Timing - I²C
24
DS726PP3
CS4525
DC ELECTRICAL CHARACTERISTICS
AGND = DGND = PGND = 0 V; All voltages with respect to ground; PWM switch rate = 384 kHz; Unless otherwise
specified.
Parameters
Min
Typ
Max
Units
Normal Operation (Note 18)
Power Supply Current
VD = 3.3 V
-
54
-
mA
Power Dissipation
VD = 3.3 V
-
180
-
mW
VD = 3.3 V
-
2.8
-
mA
2.25
2.5
2.75
V
-
-
3
mA
2.25
2.5
2.75
V
-
-
1
mA
Nominal Voltage
-
0.5*VA_REG
-
V
Output Impedance
-
23
-
kΩ
Power-Down Mode (Note 19)
Power Supply Current
VD_REG Characteristics
Nominal Voltage
DC current source
VA_REG Characteristics
Nominal Voltage
DC current source
VQ Characteristics
DC current source/sink
(Note 20)
Filt+ Nominal Voltage
Power Supply Rejection Ratio (Note 21)
Notes:
1 kHz
60 Hz
-
-
10
µA
-
VA_REG
-
V
-
60
40
-
dB
dB
18. Normal operation is defined as RST = HI.
19. Power-Down Mode is defined as RST = LOW with all input lines held static.
20. The DC current drain represents the allowed current from the VQ pin due to typical leakage through
the electrolytic de-coupling capacitors.
21. Valid with the recommended capacitor values on FILT+ and VQ. Increasing the capacitance will
increase the PSRR.
DIGITAL INTERFACE SPECIFICATIONS
AGND = DGND = PGND = 0 V; All voltages with respect to ground; Unless otherwise specified.
Parameters
Symbol
Min
Max
Units
High-Level Input Voltage
VIH
Low-Level Input Voltage
VIL
0.75*VD_REG
-
V
-
0.20*VD_REG
V
Digital Interface Signal Characteristics (Note 22)
High-Level Output Voltage
Io=2 mA
VOH
0.90*VD
-
V
Low-Level Output Voltage
Io=2 mA
VOL
-
0.2
V
Input Leakage Current
Iin
Input Capacitance
-
±10
uA
-
8
pF
PWM_SIGx Characteristics
High-Level PWM_SIGx Output Voltage
Io=2 mA
VOHPS
0.90*VD_REG
-
V
Low-Level PWM_SIGx Output Voltage
Io=2 mA
VOLPS
-
0.2
V
Notes:
22. Digital interface signals include all pins sourced from the VD supply as shown in “Digital I/O Pin
Characteristics” on page 12.
DS726PP3
25
CS4525
6. APPLICATIONS
6.1
Software Mode
Maximum device flexibility and features are available when the CS4525 is used in software mode. The available features are described in the following sections. All device configuration is achieved via the I²C control
port as described in the I²C Control Port Description and Timing section on page 64.
6.1.1
System Clocking
In software mode, the CS4525 can be clocked by a stable external clock source input on the SYS_CLK
pin or by a clock internally generated through the use of its internal oscillator driver circuit in conjunction
with an external crystal oscillator. The device automatically selects which of these clocks to use within
10 ms of the release of RST.
The internal clock is used to synchronize the input serial audio signals with the internal clock domain and
to clock the internal digital processing, sample-rate converter, and PWM modulators. It is also used to determine the sample rate of the serial audio input signals in order to automatically configure the various
internal filter coefficients.
To ensure proper operation, the CS4525 must be informed of the nominal frequency of the supplied
SYS_CLK signal or the attached crystal via the ClkFreq[1:0] bits in the Clock Config register. These bits
must be set to the appropriate value before the PDnAll bit is cleared to initiate a power-up sequence. See
the SYS_CLK Switching Specifications and XTI Switching Specifications tables on page 23 for complete
input frequency range specifications.
WARNING: The system clock source must never be removed or stopped while any of the power output
stages are powered-up (the PDnAll bit and any of the PDnOut1, PDnOut2, or PDnOut3/4 bits are cleared)
and connected to a load. Doing so may result in permanent damage to the CS4525 and connected transducers.
Referenced Control
Register Location
ClkFreq[1:0]......................... “Clock Frequency (ClkFreq[1:0])” on page 69
PDnAll ................................. “Power Down (PDnAll)” on page 89
PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 89
6.1.1.1
SYS_CLK Input Clock Mode
If an input clock is detected on the SYS_CLK pin following the release of RST, the device will automatically
use the SYS_CLK input as its clock source. The applied SYS_CLK clock signal must oscillate within the
frequency ranges specified in the SYS_CLK switching specifications table on page 23. In this mode, XTI
should be connected to ground and XTO should be left unconnected.
Figure 12 below demonstrates a typical clocking configuration using the SYS_CLK input.
Clock
Clock_In
SYS_CLK
DSP
CS4525
XTI
Reset_Out
RST
XTO
Figure 12. Typical SYS_CLK Input Clocking Configuration
26
DS726PP3
CS4525
6.1.1.2
Crystal Oscillator Mode
To use an external crystal in conjunction with the internal crystal driver, a 20 pF fundamental mode parallel resonant crystal must be connected between the XTI and XTO pins. This crystal must oscillate within
the frequency ranges specified in the XTI switching specifications table on page 23. Nothing other than
the crystal and its load capacitors should be connected to XTI and XTO. The SYS_CLK pin should be
connected to ground through a 22 kΩ pull-down resistor to prevent the CS4525 from recognizing system
noise on the SYS_CLK pin as a valid clocking signal.
In this mode, the CS4525 will automatically drive the generated internal clock out of the SYS_CLK pin.
This can be disabled with the EnSysClk bit which will cause the SYS_CLK pin to become high-impedance.
Also, the DivSysClk bit allows the frequency of the generated internal clock to be divided by 2 prior to being driven out of the SYS_CLK.
It should be noted that the internal oscillator driver is disabled when the CS4525 is in reset (RST is low).
Any external devices connected to the SYS_CLK output will not receive a clock signal until the CS4525
is taken out of reset.
If an external crystal is connected to the XTI/XTO pins while an input clock signal is present on the
SYS_CLK pin following the release of RST, then the CS4525 will automatically use the SYS_CLK pin for
its internal clock. Refer to Section 6.1.1.1 for a details about this mode of operation.
Figure 13 below demonstrates a typical clocking configuration using the crystal oscillator.
Reset
RST
XTI
XTO
RST
CS4525
SYS_CLK
DSP
Clock_In
Figure 13. Typical Crystal Oscillator Clocking Configuration
Referenced Control
Register Location
EnSysClk............................. “SYS_CLK Output Enable (EnSysClk)” on page 69
DivSysClk............................ “SYS_CLK Output Divider (DivSysClk)” on page 69
DS726PP3
27
CS4525
6.1.2
Power-Up and Power-Down
The CS4525 will remain in a completely powered-down state with the control port inaccessible until the
RST pin is brought high. Once RST is high, the control port will be accessible, but all other internal blocks
will remain powered-down until they are powered-up via the control port or until hardware mode is entered.
When an external crystal is present on the XTI/XTO pins, software mode will be automatically entered
10 ms after the release of RST. If SYS_CLK is used as an input, software mode is entered by writing to
the control port within 10 ms after the release of RST. If the control port is not written within this time, the
device will begin to operate in hardware mode.
6.1.2.1
Power-Up Sequence
1. Hold RST low until the power supplies and the input SYS_CLK (if used) are stable.
2. Bring RST high.
The device will remain in a low-power state and the control port will be accessible. The device will
automatically enter software mode after 10 ms if an external crystal is present on the XTI/XTO pins,
at which time the output SYS_CLK signal will become active.
3. If SYS_CLK is used as an input, initiate a control port write to set the PDnAll bit in register 5Fh within
10 ms following the release of RST.
This operation causes the device to enter software mode and places it in power-down mode.
4. If the LVD pin is tied low and VD, VD_REG, and VA_REG are connected to 2.5 V, clear the SelectVD
bit in the Power Ctrl register to indicate the 2.5 V VD supply level. See section 6.7 on page 63 for details.
5. If VP is connected to a supply voltage less than or equal to 14 V nominal, clear the SelectVP bit in the
Foldback Cfg register to indicate the VP supply level.
6. Write the following initialization sequence to the CS4525 registers:
– 55h to register 64h.
– 08h to register 69h.
– 00h to register 64h.
7. Other desired register settings can be loaded while keeping the PDnAll bit set. Typical initialization
settings include Input Configuration, Output Configuration, Master Volume, and Clock Frequency.
8. Clear the PDnAll bit to initiate the power-up sequence.
6.1.2.2
Power-Down Sequence
1. Set the MuteChA, MuteChB, and MuteSub bits in the Mute Control register to mute the audio output.
2. Set the PDnAll bit to power-down the device.
3. If the SYS_CLK input clock mode is used, the SYS_CLK signal may now be removed. See section
6.1.1 on page 26 for more information.
4. Bring RST low to bring the device’s power consumption to an absolute minimum.
5. Remove power.
Referenced Control
Register Location
PDnAll ................................. “Power Down (PDnAll)” on page 89
SelectVD ............................. “Select VD Level (SelectVD)” on page 88
SelectVP ............................. “Select VP Level (SelectVP)” on page 74
MuteChX ............................. “Independent Channel A & B Mute (MuteChX)” on page 84
MuteSub.............................. “Sub Channel Mute (MuteSub)” on page 85
Input Configuration.............. “Input Configuration (Address 02h)” on page 71
Output Configuration ........... “Output Configuration (Address 04h)” on page 73
Master Volume .................... “Master Volume Control (Address 57h)” on page 82
Clock Frequency ................. “Clock Frequency (ClkFreq[1:0])” on page 69
28
DS726PP3
CS4525
6.1.3
Input Source Selection
The CS4525 can accept analog or digital audio input signals. Digital audio input signals are supplied
through the serial audio input port as outlined in “Serial Audio Interfaces” on page 62. Analog audio input
signals are supplied through the internal ADC as outlined in “Analog Inputs” on page 61. The input source
is selected by the ADC/SP bit in the Input Config register.
In software mode, the serial audio input port supports I²S, Left-Justified and Right-Justified data formats.
The serial audio input port digital interface format is configured by the DIF[2:0] bits in the Input Config register.
The CS4525 internal ADC includes a dedicated high-pass filter to remove any DC content from the ADC
output signal prior to the internal ADC/serial audio input port input multiplexor. This high-pass filter can be
bypassed by clearing the EnAnHPF bit.
Referenced Control
Register Location
ADC/SP............................... “Input Source Selection (ADC/SP)” on page 71
DIF[2:0] ............................... “Input Serial Port Digital Interface Format (DIF [2:0])” on page 71
EnAnHPF ............................ “ADC High-Pass Filter Enable (EnAnHPF)” on page 71
6.1.4
Digital Sound Processing
The CS4525 implements flexible digital sound processing operations including bass management crossover, 2-way speaker crossovers, high- and low-pass shelving filters, programmable parametric EQ filters,
adaptive loudness compensation, channel mixers, and volume controls.
The digital signal flow is shown in Figure 14 below. The signal processing blocks are described in detail
in the following sections.
Stereo
Analog In
ADC
Audio
Processing
HighPass
Ch. 1
Sample
Rate
Converter
PWM
Modulator
Sample
Rate
Converter
PWM
Modulator
Sample
Rate
Converter
PWM
Modulator
Parametric EQ
High-Pass
Serial Audio
Input Port
Serial Audio
Clocks & Data
Bass/Treble
Serial Audio
Delay
Interface
Serial Audio
Data I/O
Serial Audio
Clocks & Data
Ch. 2
Adaptive
Loudness
Compensation
2-Ch Mixer
2.1 Bass Mgr
Sub
Linkwitz-Riley
Crossover
Auxiliary
Serial Port
PWM
Output
Config
Gate
Drive
Power
Stage
Amplifier
Out 1
Gate
Drive
Power
Stage
Amplifier
Out 2
Gate
Drive
Power
Stage
Amplifier
Out 3
Gate
Drive
Power
Stage
Amplifier
Out 4
PWM Modulator
Output 1
PWM Modulator
Output 2
De-Emphasis
Volume
Temperature Sense
Temperature
Sense
Thermal Foldback
Thermal Limiter
Sub
Loudness
Ch. A HPF
Ch. A LPF
Ch. B HPF
Ch. B LPF
Sensitivity
X-Over
Limiter
Master Vol Control
Ch. B
Ch. Vol Control
Ch. A
Bass Manager
Treble Tone Ctrl
Param. EQ
Ch. B
Bass Tone Ctrl
Mixer
Ch. A
De-Emphasis
Right
Pre-Scaler
Serial Audio
Data In
High-Pass Filter
Ch. A
Left
Ch. A HPF
Ch. 1
Ch. A LPF
Ch. B
Ch. 2
Sub
Ch. B HPF
Aux Serial Data Select
Ch. B LPF
Data to
Aux Port
Figure 14. Digital Signal Flow
DS726PP3
29
CS4525
6.1.4.1
Pre-Scaler
Applying any gain to a full-scale signal in the digital domain will cause the signal to clip. To prevent this,
a pre-scaler block is included prior to the internal digital signal processing blocks. This allows the input
signal to be attenuated before processing to ensure that any signal boosting, such as gain in a shelving
filter, will not cause a channel to clip.
The pre-scaler block allows up to -14.0 dB of attenuation in 2.0 dB increments and is controlled with the
PreScale[2:0] bits.
Referenced Control
Register Location
PreScale[2:0]....................... “Pre-Scale Attenuation (PreScale[2:0])” on page 75
6.1.4.2
Digital Signal Processing High-Pass Filter
The CS4525 includes a high-pass filter at the beginning of the digital signal processing chain to remove
any DC content from the input signal prior to the remaining internal digital signal processing blocks. The
high-pass filter operates by continuously subtracting a measure of the DC offset from the input signal and
may be used regardless of the input data source.
The digital signal processing high-pass filter can be disabled by clearing the EnDigHPF bit.
Referenced Control
Register Location
EnDigHPF ........................... “Digital Signal Processing High-Pass Filter (EnDigHPF)” on page 77
6.1.4.3
Channel Mixer
The CS4525 implements independent channel mixers to provide for both mono mixes and channel swaps
for the left and right channels. The channel mixers are controlled by the LChMix[1:0] and RChMix[1:0] bits
in the Mixer Config register.
To allow stereo operation when a mono mix is configured, when the HP_DETECT/MUTE pin is configured
for headphone detection (the HP/Mute bit is set), the operation of the left channel mixer is affected by the
active state of the headphone detection input signal. In this configuration, when the left channel mixer is
configured for a mono mix (LChMix[1:0] = 01 or 10) and the headphone detection input signal becomes
active, the left channel mixer will be automatically reconfigured to output the left channel, thereby disabling the mono mix. When the headphone detection input signal becomes inactive, the mixer will be automatically reconfigured to operate as dictated by the LChMix[1:0] bits.
It should be noted that the right channel mixer output is unaffected by the headphone detection input signal and will always operate as dictated by the RChMix[1:0] bits.
Referenced Control
Register Location
LChMix[1:0] ......................... “Left Channel Mixer (LChMix[1:0])” on page 76
RChMix[1:0] ........................ “Right Channel Mixer (RChMix[1:0])” on page 76
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 70
30
DS726PP3
CS4525
6.1.4.4
De-Emphasis
The CS4525 includes an on-chip digital de-emphasis filter optimized for a sample rate of 44.1 kHz to accommodate audio recordings that utilize 50/15 µs pre-emphasis equalization as a means of noise reduction. The filter response is shown in Figure 15. The de-emphasis filter is enabled and disabled by the
DeEmph bit in the Tone Config register.
Gain (dB)
T1=50 µs
0 dB
T2 = 15 µs
-10 dB
Frequency (Hz)
Nominal Sample Rate
32 kHz, 44.1 kHz, 48 kHz
96 kHz
F1
0.07218 Fs
0.03609 Fs
F2
0.24059 Fs
0.12030 Fs
Normalized to Fs
Figure 15. De-Emphasis Filter
Referenced Control
Register Location
DeEmph .............................. “De-Emphasis Control (DeEmph)” on page 76
6.1.4.5
Tone Control
The CS4525 implements configurable bass and treble shelving filters to easily accommodate system tone
control requirements. Each shelving filter has 4 selectable corner frequencies, and provides a cut/boost
range from -10.5 dB to +12.0 dB in 1.5 dB increments. The tone control is enabled by the EnToneCtrl bit
in the Tone Config register.
Each tone control is implemented with one of two preset internal filter sets. One set is optimized for a
32 kHz sample rate, and the other is optimized for 44.1 kHz, 48 kHz, and 96 kHz sample rates. The
CS4525 automatically detects the input sample rate and chooses the appropriate filter set to apply. The
available corner frequencies are shown in tables 2 and 3 below and are configured with the BassFc[1:0]
and TrebFc[1:0] bits in the Tone Config register.
Note that the corner frequency of each filter set scales linearly with the input sample rate.
When the internal ADC is used as the serial audio data source, the input sample rate is nominally 48 kHz
and the corresponding shelving frequency corners are available.
Input Sample Rate
32 kHz
44.1 kHz
48 kHz, 96 kHz
Bass Fc 0
50 Hz
48 Hz
52 Hz
Bass Fc 1
100 Hz
96 Hz
104 Hz
Bass Fc 2
200 Hz
192 Hz
208 Hz
Bass Fc 3
250 Hz
240 Hz
260 Hz
Table 2. Bass Shelving Filter Corner Frequencies
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CS4525
Input Sample Rate
32 kHz
44.1 kHz
48 kHz, 96 kHz
Treble Fc 0
5.0 kHz
4.8 kHz
5.2 kHz
Treble Fc 1
7.0 kHz
6.7 kHz
7.3 kHz
Treble Fc 2
10.0 kHz
9.6 kHz
10.4 kHz
Treble Fc 3
15.0 kHz
14.4 kHz
15.6 kHz
Table 3. Treble Shelving Filter Corner Frequencies
The cut/boost level of the bass and treble shelving filters are set by the Bass[3:0] and Treble[3:0] bits in
the Tone Control register.
Referenced Control
Register Location
EnToneCtrl .......................... “Tone Control Enable (EnToneCtrl)” on page 77
TrebFc[1:0] .......................... “Treble Corner Frequency (TrebFc[1:0])” on page 77
BassFc[1:0] ......................... “Bass Corner Frequency (BassFc[1:0])” on page 77
Treble[3:0] ........................... “Treble Gain Level (Treb[3:0])” on page 78
Bass[3:0] ............................. “Bass Gain Level (Bass[3:0])” on page 78
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CS4525
6.1.4.6
Parametric EQ
The CS4525 implements 5 fully programmable parametric EQ filters.
The filters are implemented in the bi-quad form shown below.
x[n]
b0
y[n]
Z -1
Z -1
b1
a1
Z -1
Z -1
b2
a2
Figure 16. Bi-Quad Filter Architecture
This architecture is represented by the equation shown below where y[n] represents the output sample
value and x[n] represents the input sample value.
y[n] = b0x[n] + b1x[n-1] + b2x[n-2] + a1y[n-1] + a2y[n-2]
Equation 1. Bi-Quad Filter Equation
The coefficients are represented in binary form by 24-bit signed values stored in 3.21 two’s complement
format. The 3 MSB’s represent the sign bit and the whole-number portion of the decimal coefficient, and
the 21 LSB’s represent the fractional portion of the decimal coefficient. The coefficient values must be in
the range of -4.00000 decimal (80 00 00 hex) to 3.99996 decimal (7F FF FF hex).
The binary coefficient values are stored in registers 0Ah - 54h. Each 24-bit coefficient is split into 3 bytes,
each of which is mapped to an individually accessible register location. See the “Register Quick Reference” section beginning on page 66 for the specific register locations for each coefficient.
By default, all b0 coefficients are set to 1 decimal, and all other coefficients are set to 0 decimal. This implements a pass-through function.
The parametric equalizers be independently enabled and disabled for channels A and B with the EnChAPEq and EnChBPEq bits located in the EQ Config register.
Referenced Control
Register Location
EnChAPEq .......................... “Enable Channel A Parametric EQ (EnChAPEq)” on page 79
EnChBPEq .......................... “Enable Channel B Parametric EQ (EnChBPEq)” on page 79
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CS4525
6.1.4.7
Adaptive Loudness Compensation
The CS4525 includes adaptive loudness compensation to enhance the audibility of program material at
low volume levels. The adaptive loudness compensation feature operates by varying the bass and treble
boost of the tone control shelving filters as the volume level changes.
The level of boost added to the shelving filters is determined by the average of the effective volume settings of channels A and B after the master volume control. As this average volume setting decreases from
0 dB, the boost of the bass and treble shelving filters is gradually increased until it reaches the maximum
boost level of 12.0 dB. As the volume is increased, the boost applied due to the adaptive loudness compensation feature will be gradually removed until it reaches the level specified by the Treble[3:0] and
Bass[3:0] bits in the Tone Control register.
The adaptive loudness compensation feature is enabled by setting the Loudness bit in the Tone Config
register. When the loudness feature is enabled, it immediately evaluates the effective average volume and
applies bass and treble boost accordingly. When disabled, any treble or bass boost applied due to the
loudness feature will be removed.
Because the adaptive loudness compensation filter operates by adjusting the boost level of the tone control shelving filters, it is necessary that they be enabled with the EnToneCtrl bit in the Tone Config register
in order for the loudness feature to be operational. If the tone control filters are disabled, the adaptive loudness compensation feature will not be functional.
Referenced Control
Register Location
Loudness............................. “Adaptive Loudness Compensation Control (Loudness)” on page 76
EnToneCtrl .......................... “Tone Control Enable (EnToneCtrl)” on page 77
TrebFc[1:0] .......................... “Treble Corner Frequency (TrebFc[1:0])” on page 77
BassFc[1:0] ......................... “Bass Corner Frequency (BassFc[1:0])” on page 77
Treble[3:0] ........................... “Treble Gain Level (Treb[3:0])” on page 78
Bass[3:0] ............................. “Bass Gain Level (Bass[3:0])” on page 78
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CS4525
6.1.4.8
Bass Management
The CS4525 implements a dedicated stereo 24 dB/octave Linkwitz-Riley crossover with adjustable crossover frequency to achieve bass management for 2.1 configurations. The filter’s stereo high-pass outputs
are used to drive the full-range speakers, and its stereo low-pass outputs are each attenuated by 6 dB
and summed to drive the sub channel.
The bass management crossover is implemented with one of two preset internal filter sets. One set is optimized for a 32 kHz sample rate, and the other is optimized for 44.1 kHz, 48 kHz, and 96 kHz sample
rates. The CS4525 automatically detects the input sample rate and chooses the appropriate filter set to
apply. The available bass management cross-over frequencies are shown in Table 4 below and are configured with the BassMgr[2:0] bits in the EQ Config register.
Note that the corner frequency of each filter set scales linearly with the input sample rate.
When the internal ADC is used as the serial audio data source, the input sample rate is nominally 48 kHz
and the corresponding shelving frequency corners are available.
Bass Manager Freq 1
Bass Manager Freq 2
Bass Manager Freq 3
Bass Manager Freq 4
Bass Manager Freq 5
Bass Manager Freq 6
Bass Manager Freq 7
32 kHz
80 Hz
120 Hz
160 Hz
200 Hz
240 Hz
280 Hz
320 Hz
Input Sample Rate
44.1 kHz
77 Hz
115 Hz
153 Hz
192 Hz
230 Hz
268 Hz
307 Hz
48 kHz, 96 kHz
83 Hz
125 Hz
167 Hz
209 Hz
250 Hz
292 Hz
334 Hz
Table 4. Bass Management Cross-Over Frequencies
The BassMgr[2:0] bits also allow the bass manager to be disabled. When disabled, the bass management
crossover is bypassed and no signal is presented on the sub channel.
To allow full-range headphone operation, when the HP_DETECT/MUTE pin is configured for headphone
detection (the HP/Mute bit is set), the operation of the bass manager is affected by the active state of the
headphone detection input signal. In this configuration, when the bass manager is enabled, (BassMgr[2:0]
bits not equal to ‘000’) and the headphone detection input signal becomes active, the bass manager will
be automatically disabled. When the headphone detection input signal becomes inactive, the bass manager will be automatically reconfigured to operate as dictated by the BassMgr[2:0] bits.
Referenced Control
Register Location
BassMgr[2:0] ....................... “Bass Cross-Over Frequency (BassMgr[2:0])” on page 79
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 70
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CS4525
6.1.4.9
Volume and Muting Control
The CS4525’s volume control architecture provides the ability to control the level of each output channel
on both an individual and master basis.
Individual control allows the volume and mute state of a single channel to be changed independently from
the other channels within the device. The CS4525 provides three individual volume and muting controls,
each permanently assigned to one channel within the device. The three individual volume controls,
ChAVol, ChBVol, and SubVol, can gain or attenuate channel A, channel B, or the sub channel (respectively) from +24 dB to -103 dB in 0.5 dB steps. The three individual mute controls, MuteChA, MuteChB,
and MuteSub bits, can mute channel A, channel B, or the sub channel (respectively).
Master control allows the volume of all channels to be changed simultaneously by offsetting each channel’s individual volume setting by an additional +24 dB to -103 dB in 0.5 dB steps. By default, master volume is set to +3dB; if the CS4525 is being used to control the application’s master volume, then it is
recommended to change this value to a comfortable listening level before enabling the PWM powered outputs. Master volume control is accomplished via the Master Vol register.
The PWM outputs can be configured to output silence as a modulated signal or an non-modulated 50%
duty cycle signal during a mute condition. This selection is achieved via the Mute50/50 bit in the
Volume Cfg register.
The AutoMute bit in the same register dictates whether the device will automatically mute after the reception of 8192 consecutive samples of static 0 or -1. When the AutoMute function is enabled, a single sample
of non-static data will cause the automatic mute to be released.
The CS4525 implements soft-ramp and zero-crossing detection capabilities to provide noise-free level
transitions. When the zero-crossing function is enabled, all volume and muting changes are made on an
output signal zero-crossing. The zero-crossing detection function is implemented independently for each
channel. When the soft-ramp function is enabled, the volume is ramped from its initial to its final level at
a rate of ½ dB every 4 samples for 32, 44.1, and 48 kHz sample rates, and ½ dB every 8 samples for a
96 kHz sampling rate.
All volume and muting changes are implemented as dictated by the soft-ramp and zero-cross settings
configured by the SZCMode[1:0] bits in the Volume Cfg register.
Referenced Control
Register Location
ChXVol ................................ “Channel A and B Volume Control (Address 58h & 59h)” on page 83
SubVol................................. “Sub Channel Volume Control (Address 5Ah)” on page 83
MuteChX ............................. “Independent Channel A & B Mute (MuteChX)” on page 84
MuteSub.............................. “Sub Channel Mute (MuteSub)” on page 85
Master Vol ........................... “Master Volume Control (Address 57h)” on page 82
Mute50/50 ........................... “Enable 50% Duty Cycle for Mute Condition (Mute50/50)” on page 80
AutoMute............................. “Auto-Mute (AutoMute)” on page 80
SZCMode ............................ “Soft Ramp and Zero Cross Control (SZCMode[1:0])” on page 80
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CS4525
6.1.4.10 Peak Signal Limiter
When enabled, the limiter monitors the digital output following the volume control block, detects when
peak levels exceed a selectable maximum threshold level and lowers the volume at a programmable attack rate until the signal peaks fall below the maximum threshold. When the signal level falls below a selectable minimum threshold, the volume returns to its original level (as determined by the individual and
master volume control registers) at a programmable release rate. Attack and release rates are affected
by the soft ramp/zero cross settings and sample rate, Fs.
Recommended settings: Best limiting performance may be realized with the fastest attack and slowest
release setting with soft ramp enabled in the control registers. Use the “minimum” bits to set a threshold
slightly below the maximum threshold to cushion the sound as the limiter attacks and releases.
Input
Max[2:0]
Limiter
Attack/Release Sound
Cushion
Volume
Attack/Release Sound
Cushion
Output
(after Limiter)
Min[2:0]
ARate[5:0]
RRate[5:0]
Figure 17. Peak Signal Detection & Limiting
By default, the limiter affects all channels when the maximum threshold is exceeded on any single channel. This default functionality is designed to keep all output channels at the same volume level while the
limiter is in use. This behavior can be disabled by clearing the LimitAll bit in the Limiter Cfg 1 register.
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CS4525
When the LimitAll feature is activated, attenuation will be applied to all channels when a single channel
exceeds the maximum threshold and released when the level of all channels is below the minimum
threshold. When the LimitAll feature is de-activated, limiter attenuation will be applied and released on a
per-channel basis and will only affect the channel on which the limiter event occurred.
The limiter can be enabled by setting the EnLimiter bit in the Limiter Cfg 1 register
The limiter can also be used in conjunction with the thermal limiter function to provide thermal error protection to the CS4525. The thermal limiter function is described in Thermal Limiter on page 39.
Referenced Control
Register Location
EnLimiter ............................. “Peak Detect and Limiter Enable (EnLimiter)” on page 86
LimitAll................................. “Peak Signal Limit All Channels (LimitAll)” on page 86
Max[2:0] .............................. “Maximum Threshold (Max[2:0])” on page 85
Min[2:0] ............................... “Minimum Threshold (Min[2:0])” on page 85
ARate[5:0] ........................... “Limiter Attack Rate (ARate[5:0])” on page 87
RRate[5:0] ........................... “Limiter Release Rate (RRate[5:0])” on page 87
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CS4525
6.1.4.11 Thermal Limiter
The CS4525 implements a thermal limiter function to provide a quick corrective response to potentially
damaging thermal overload conditions. The thermal limiter feature operates by sensing the presence of
a thermal warning condition and, in response, utilizes the peak signal limiter to dynamically limit the signal
amplitude prior to the PWM modulators. This effectively limits the output power capability of the device,
thereby allowing the temperature to reduce to acceptable levels without fully interrupting operation.
The thermal limiter is enabled by the EnThLim bit in the Limiter Configuration 3 register. When enabled,
the thermal limiter will trigger once when either of the following conditions is met:
1. The junction temperature crosses the thermal warning threshold for the first time after the thermal
limiter function is enabled.
2. The junction temperature is greater than the thermal warning threshold at the time the thermal limiter
function is enabled.
Once triggered, the thermal limiter will remain in a triggered state until the RST pin is driven low.
When in the triggered state, the thermal limiter will engage whenever the EnThLim bit is set. While engaged, the thermal limiter utilizes the peak signal limiter function to dynamically limit the signal amplitude
prior to the PWM modulators via the peak signal limiter; the characteristics of this limiting function are described in Section 6.1.4.10 on page 37. If the thermal limiter is engaged and the peak signal limiter is disabled via the EnLimiter bit, the peak signal limiter will be automatically enabled and its minimum and
maximum thresholds will be set to -3 dB. If the thermal limiter is engaged and the peak signal limiter is
enabled, an additional -3dB will be automatically applied to the minimum and maximum thresholds established in the Limiter Cfg 1 register. The automatic enabling of the peak signal limiter and the automatic
application of additional attenuation to its thresholds is done internal to the CS4245; the values of the EnLimiter, Min[2:0], and Max[2:0] bits in the Limiter Cfg 1 register are not affected by the engagement of the
thermal limiter function.
It should be noted that the thermal limiter can only be triggered once following the release of the RST signal. Once it has triggered, the thermal limiter’s attenuation will always be implemented while the thermal
limiter is enabled. If the thermal limiter is disabled after it has triggered, the internal enabling of the peak
signal limiter and the additional -3 dB attenuation applied to its minimum and maximum thresholds will be
released. In this state, the peak signal limiter’s operation will follow the EnLimiter, Min[2:0], and Max[2:0]
bits with no internal modification. If EnThLim is set again before the CS4525 has been reset (by toggling
the RST pin low and then high), thermal limiting will engage immediately.
Referenced Control
Register Location
EnThLim.............................. “Enable Thermal Limiter (EnThLim)” on page 87
EnLimiter ............................. “Peak Detect and Limiter Enable (EnLimiter)” on page 86
Max[2:0] .............................. “Maximum Threshold (Max[2:0])” on page 85
Min[2:0] ............................... “Minimum Threshold (Min[2:0])” on page 85
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CS4525
6.1.4.12 Thermal Foldback
The CS4525 implements comprehensive thermal foldback features to guard against damaging thermal
overload conditions. Thermal foldback is similar to the thermal limiting described on page 39 in that both
features attenuate the output signal in response to thermal warnings conditions; however, thermal foldback will attenuate as a function of how long thermal warning has been active whereas thermal limiter
always limits by a constant amount. Also, the thermal foldback feature will deactivate once the thermal
warning condition ceases while the thermal limiter will remain active once triggered until the RST pin is
driven low.
The thermal foldback algorithm begins limiting the volume of the digital audio input to the amplifier stage
as the junction temperatures rise above the maximum safe operating range specified by the thermal warning trigger point listed in the PWM Power Output Characteristics table on page 20. This effectively limits
the output power capability of the device, thereby allowing the temperature to reduce to acceptable levels
without fully interrupting operation. As the device cools, the applied attenuation is gradually released until
a new thermal equilibrium is reached or all applied attenuation has been released thereby allowing the
device to again achieve its full output power capability.
Attenuation applied due to thermal foldback reduces the audio output level in a linear manner. Figure 18
below demonstrates the foldback process.
Foldback Attack Delay
AttackDly[1:0]
tdelay
tdelay
tdelay
tdelay
tdelay
2
2
2
Thermal Warning
Threshold
1
1
2
3
1
When the junction temperature crosses the thermal warning threshold, the foldback attack delay timer is started.
2
When the foldback attack delay timer reaches tdelay seconds, the junction temperature is checked. If the junction
temperature is above the thermal warning threshold, the output volume level is lowered by 0.5 dB and the foldback
attack timer is restarted.
The junction temperature is checked after each foldback attack timer timeout, and if necessary, the output volume level
is lowered accordingly.
If the junction temperature is found to be below the thermal warning threshold, the foldback attack timer is restarted
once again, but the output volume level is not altered. The foldback algorithm then proceeds to step 3.
3
The junction temperature is checked once again after the next foldback attack timer timeout. If it has remained below the
thermal warning threshold since the last check, the device will begin to release any attenuation applied as a result of the
foldback event. Setting the LockAdj bit will prevent the device from removing the applied attenuation when the thermal
overload condition has cleared.
If the junction temperature crosses the thermal warning threshold again, the foldback algorithm will once again enter
step 1.
Figure 18. Foldback Process
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CS4525
The AttackDly[1:0] bits in the Foldback Cfg register allow the foldback attack delay timeout period to be
adjusted from approximately 0.5 seconds to approximately 2.0 seconds. The maximum attenuation applied by the thermal foldback algorithm can be restricted to -30 dB by setting the EnFloor bit in the same
register.
The foldback adjustment lock feature causes the attenuation applied by the foldback algorithm to be maintained after the foldback condition has subsided. The applied attenuation will continue to be applied until
the master volume or all active channel volume controls are lowered below the foldback attenuation level,
or until a subsequent foldback condition occurs causing the applied attenuation to be lowered further. If
the foldback algorithm applies attenuation while this feature is enabled, when the feature is subsequently
disabled, the applied attenuation will be gradually released as long as the temperature remains within the
safe operating range. This foldback lock adjustment feature is enabled by the LockAdj bit in the
Foldback Cfg register.
Thermal warnings will only affect the foldback algorithm and cause attenuation to be applied when enabled by the EnTherm bit in the Foldback Cfg register.
The CS4525 can be configured to accept an external thermal warning indicator input. When in this configuration, an active input signal indicates that a thermal warning threshold has been exceeded. If thermal
foldback is enabled, the foldback algorithm will respond as described above making no distinction between an internal or external thermal warning condition. See “External Warning Input Port” on page 44 for
more information.
Referenced Control
Register Location
EnTherm ............................. “Enable Thermal Foldback (EnTherm)” on page 74
AttackDly[1:0] ...................... “Foldback Attack Delay (AttackDly[1:0])” on page 75
EnFloor................................ “Enable Foldback Floor (EnFloor)” on page 75
LockAdj ............................... “Lock Foldback Adjust (LockAdj)” on page 74
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CS4525
6.1.4.13 2-Way Crossover & Sensitivity Control
The CS4525 implements a dedicated stereo 24 dB/octave Linkwitz-Riley crossover filter with adjustable
cross-over frequency and sensitivity control to facilitate 2-way speaker configurations. The filter’s highpass output can be used to drive the tweeter, and its low-pass output can be used to drive the midrange/woofer. The sensitivity control is included to adjust the level of the high-pass and low-pass outputs
to compensate for differences in the tweeter and mid-range/woofer sensitivity.
The two-way crossover is implemented with one of two preset internal filter sets. One set is optimized for
a 32 kHz sample rate, and the other is optimized for 44.1 kHz, 48 kHz, and 96 kHz sample rates. The
CS4525 automatically detects the input sample rate and chooses the appropriate filter set to apply. The
available cross-over frequencies are shown in Table 5 below and are configured with the 2WayFreq[2:0]
bits in the Volume Cfg register.
Note that the corner frequency of each filter set scales linearly with the input sample rate.
When the internal ADC is used as the serial audio data source, the input sample rate is nominally 48 kHz
and the corresponding shelving frequency corners are available.
X-Over Freq 0
X-Over Freq 1
X-Over Freq 2
X-Over Freq 3
X-Over Freq 4
X-Over Freq 5
X-Over Freq 6
X-Over Freq 7
32 kHz
2.0 kHz
2.2 kHz
2.4 kHz
2.6 kHz
2.8 kHz
3.0 kHz
3.2 kHz
3.4 kHz
Input Sample Rate
44.1 kHz
1.92 kHz
2.11 kHz
2.30 kHz
2.49 kHz
2.68 kHz
2.88 kHz
3.07 kHz
3.26 kHz
48 kHz, 96 kHz
2.09 kHz
2.30 kHz
2.50 kHz
2.71 kHz
2.92 kHz
3.13 kHz
3.34 kHz
3.55 kHz
Table 5. 2-Way Cross-Over Frequencies
The sensitivity level of the high- and low-pass outputs of the crossovers can be independently adjusted
from 0 dB to -7.5 dB in 0.5 dB increments. The maximum attenuation level of -7.5 dB will compensate for
an approximate 4 dB difference in sound pressure level (SPL) between the tweeter and the midrange/woofer drivers. The sensitivity is adjusted using the HighPass[3:0] and LowPass[3:0] bits in the
Sensitivity register. Note that these bits affect the sensitivity of both channel A and channel B high- and
low-pass outputs.
The 2-way crossover can be enabled by setting the En2Way bit in the Volume Cfg register.
Referenced Control
Register Location
En2Way............................... “Enable 2-Way Crossover (En2Way)” on page 81
2WayFreq[2:0]..................... “2-Way Cross-Over Frequency (2WayFreq[2:0])” on page 81
HighPass[3:0]...................... “Channel A and Channel B High-Pass Sensitivity Adjust (HighPass[3:0])” on page 82
LowPass[3:0]....................... “Channel A and Channel B Low-Pass Sensitivity Adjust (LowPass[3:0])” on page 81
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CS4525
6.1.5
Auxiliary Serial Output
The CS4525 includes a stereo auxiliary serial output which allows an external device to leverage on its
internal signal processing and routing capabilities. The auxiliary serial output can receive its data from any
of the sources shown in the Digital Signal Flow diagram on page 29.
The supported output data routing configurations are shown in Table 6 below. By default, the serial port
is configured to output channels A and B on the auxiliary output data left and right channels respectively.
LChDSel[1:0]
00
01
10
11
Aux Left Channel Data
Channel A
Channel B
Sub Channel
Channel B X-Over LPF
RChDSel[1:0]
00
01
10
11
Aux Right Channel Data
Channel A
Channel B
Sub Channel
Channel B X-Over HPF
Table 6. Auxiliary Serial Port Data Output
The data output on each channel of AUX_SDOUT is set by the LChDSel[1:0] and RChDSel[1:0] bits in
the Aux Port Configuration register. The frequencies of AUX_LRCK and AUX_SCLK will vary based upon
the whether the serial input or analog input is being used and the frequency of the system clock for the
CS4525; the nominal values for these clocks are listed in Table 7. The characteristics of AUX_SCLK,
AUX_LRCK, and AUX_SDOUT are described in the AUX Serial Audio I/O Port Switching Specifications
table on page 22.
Signal
Applied System Clock from either
SYS_CLK or External Crystal
Frequency of LRCK Input
ADC/SP = 0
(Digital Input Mode)
18.432, 24.576, or 27.000MHz
32kHz, 44.1kHz,
or 48kHz
Nominal Frequency of AUX_SCLK
Frequency of
Output
SCLK Input
Nominal Frequency of AUX_LRCK
Frequency of
Output
LRCK Input
ADC/SP = 1
(Analog Input Mode)
18.432MHz
96kHz
Frequency of
SCLK Input / 2
Frequency of
LRCK Input / 2
24.576MHz
27.000MHz
Not Applicable
2.304MHz
3.072MHz
3.375MHz
48kHz
48kHz
52.734kHz
Table 7. Nominal Switching Frequencies of the Auxiliary Serial Output
The auxiliary port can be enabled using the EnAuxPort bit. When enabled, the port operates as a master
and clocks out data in the format dictated by the AuxI²S/LJ bit. When disabled, the AUX_LRCK,
AUX_SCLK, and AUX_SDOUT pins continuously drive a logic ‘0’. It should be noted that when the
CS4525 is configured for analog input, the AUX_LRCK, AUX_SCLK, and AUX_SDOUT pins will continuously drive a logic ‘0’ if either the PDnADC bit or PDnAll bit is set.
Referenced Control
Register Location
EnAuxPort ........................... “Enable Aux Serial Port (EnAuxPort)” on page 72
LChDSel[1:0]....................... “Aux Serial Port Left Channel Data Select (LChDSel[1:0])” on page 73
RChDSel[1:0] ...................... “Aux Serial Port Right Channel Data Select (RChDSel[1:0])” on page 72
AuxI²S/LJ............................. “Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ)” on page 72
PDnADC.............................. “Power Down ADC (PDnADC)” on page 88
PDnAll ................................. “Power Down (PDnAll)” on page 89
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CS4525
6.1.6
Serial Audio Delay & Warning Input Port
The CS4525 includes a configurable delay and warning port to allow easy system integration of external
lip-sync delay devices or warning inputs from external amplifiers. The port can be configured as a serial
audio delay interface, an external warning input port, or disabled by the DlyPortCfg[1:0] bits in the Aux
Config register. When disabled, the DLY_SDOUT and DLY_SDIN/EX_TWR pins become high-impedance.
Referenced Control
Register Location
DlyPortCfg........................... “Delay & Warning Port Configuration (DlyPortCfg[1:0])” on page 72
6.1.6.1
Serial Audio Delay Interface
Video processing and reproduction circuitry in digital video display devices can often introduce noticeably
more delay than is introduced by the device’s audio processing and reproduction circuitry. This can result
in a phenomenon known as lip-synch delay - a delay present between the video and audio content being
reproduced.
To help overcome this problem, the CS4525 delay and warning port can be configured as serial audio
delay interface. This interface consists of a serial audio input/output port to facilitate the use of an external
serial audio delay device. The port routes the serial data from the selected input source (the ADC or the
serial input port) out to an external serial audio delay device, and then back in to the CS4525 internal digital sound processing blocks. The delay serial audio interface signals include DLY_SDOUT and
DLY_SDIN/EX_TWR and are clocked from AUX_LRCK and AUX_SCLK. The serial data is output on the
DLY_SDOUT pin and input on the DLY_SDIN/EX_TWR in the format specified by the AuxI²S/LJ bits in
the Aux Config register. Because the delay interface uses the auxiliary port clock signals, the auxiliary serial port must be enabled using the EnAuxPort bit in the Aux Port Configuration register to allow the delay
interface to operate properly.
Referenced Control
Register Location
AuxI²S/LJ............................. “Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ)” on page 72
EnAuxPort ........................... “Enable Aux Serial Port (EnAuxPort)” on page 72
6.1.6.2
External Warning Input Port
When implementing external PWM power stage devices with thermal warning indicator outputs, it can be
useful to provide these warning signals as an input to the internal thermal foldback algorithm. This allows
the CS4525 to automatically respond to the external devices’ thermal warning conditions without completely disrupting the system’s operation.
When configured as an external warning input port, the DLY_SDIN/EX_TWR is an active-low thermal
warning input to the foldback algorithm and the DLY_SDOUT pin becomes high-impedance.
In order for the foldback algorithm to act on the external thermal warning input signal, the thermal foldback
algorithm must be enabled by the EnTherm bit in the Foldback Cfg register. See “Thermal Foldback” on
page 40 for more information.
Referenced Control
Register Location
EnTherm ............................. “Enable Thermal Foldback (EnTherm)” on page 74
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6.1.7
Powered PWM Outputs
The CS4525’s 3 internal modulators can be used to generate multiple powered PWM output configurations to enable a wide variety of system implementations. The CS4525 also implements PWM Popguard
to minimize output transients in half-bridge configurations.
6.1.7.1
Output Channel Configurations
Three PWM power output configurations are supported as shown in Table 8 below. The configurations
support stereo full-bridge, stereo half-bridge with full-bridge sub, and mono parallel full-bridge output.
OutputCfg[1:0]
00
Power Configuration
2 Ch. Full-Bridge
01
2 Ch. Half-Bridge
+
1 Ch. Full-Bridge
10
1 Ch. Parallel Full-Bridge
Output Signal
Channel 1 +
Channel 1 Channel 2 +
Channel 2 Channel 1 +
Channel 2 +
Sub Channel +
Sub Channel Channel 1 +
Channel 1 -
Output Pin(s)
OUT1
OUT2
OUT3
OUT4
OUT1
OUT2
OUT3
OUT4
OUT1, OUT2
OUT3, OUT4
Table 8. PWM Power Output Configurations
The configurations are selected by the OutputCfg[1:0] bits in the Output Cfg register and must only be
changed when the device is in power-down mode (the PDnAll bit is set). Any attempt to write the OutputCfg[1:0] bits while the device is powered-up will be ignored.
It should be noted that signals on channels 1, 2 and the sub channel are dependent upon the digital sound
processing blocks being used. For instance, if the 2-way crossover is enabled, channel 1 and 2 contain
the 2-way crossover channel A high- and low-pass outputs respectively. For more information, see the
Digital Sound Processing section and Figure 14 on page 29.
Referenced Control
Register Location
OutputCfg[1:0]..................... “Output Configuration (OutputCfg[1:0])” on page 73
PDnAll ................................. “Power Down (PDnAll)” on page 89
6.1.7.2
PWM Popguard Transient Control
The CS4525 uses Popguard technology to minimize the effects of power-up and power-down output transients commonly produced by half-bridge, single supply amplifiers implemented with external DC-blocking capacitors connected in series with the audio outputs.
The PWM Popguard feature operates by linearly ramping the PWM power outputs up to and down from
their bias point of VP/2 when a channel is powered up and down respectively using the PDnOutX or PDnAll bits. This gradual voltage ramp minimizes output transients while the DC blocking capacitor is
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CS4525
charged and discharged. The Popguard technology has no effect on the PWM_SIG outputs nor the auxiliary serial output.
+8V to +18V
VP
0.033 uF
M
RA
P
CA OUT1
P_
Halfbridge
Filter
Left
Speaker
OUT2
Halfbridge
Filter
Right
Speaker
Fullbridge
Filter
Subwoofer
CS4525
OUT3
OUT4
Figure 19. Popguard Connection Diagram
The PWM Popguard feature is disabled by default; to enable it, the RmpSpd[1:0] register must be set to
any value other than 11. The PWM Popguard feature should only be used when the power outputs are
configured for stereo half-bridge with full-bridge sub per Section 6.1.7.1. The RAMP_CAP pin must be
connected to the VP supply through a 0.033 µF capacitor whenever the PWM Popguard technology is
enabled, as shown in Figure 19.
Typical Ramp Up Times
VP Voltage
RmpSpd[1:0] = 00
RmpSpd[1:0] = 01
RmpSpd[1:0] = 10
RmpSpd[1:0] = 11
12 V
2.16 seconds
2.20 seconds
2.20 seconds
Instant (No Ramp)
15 V
1.74 seconds
1.76 seconds
1.78 seconds
Instant (No Ramp)
18 V
1.40 seconds
1.42 seconds
1.44 seconds
Instant (No Ramp)
Table 9. Typical Ramp Times for Various VP Voltages
The output ramp time will vary depending on the voltage applied to VP and the value of the RmpSpd[1:0]
bits; typical ramp times are listed in Table 9. All output channels are affected by the RmpSpeed[1:0] bits,
and PWM Popguard feature is disabled by default.
Referenced Control
Register Location
RmpSpeed[1:0] ................... “Ramp Speed (RmpSpd[1:0])” on page 75
PDnAll ................................. “Power Down (PDnAll)” on page 89
PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 89
6.1.8
Logic-Level PWM Outputs
The CS4525 has two configurable logic-level PWM outputs, PWM_SIG1 and PWM_SIG2. These outputs
can be used as either digital input to an external PWM amplifier such as the CS4412, or as an analog
input to a headphone amplifier or a line-out amplifier.
To eliminate power-up pops when used to supply an external PWM amplifier, the CS4525 implements the
same click-free start-up function on the PWM_SIG outputs as it does for its own powered PWM outputs.
This function can only be utilized if the PWM amplifier has an initial transition delay feature, such as the
CS4412A. To eliminate power-up and power-down pops when used to supply an analog output circuit,
the PWM_SIG outputs support a high-impedance state that is controlled by the HiZPSig bit in the
EQ Config register. This bit is active-low and cleared by default. To use the PWM_SIG outputs, the HiZPSig bit must be set to enable the PWM_SIG output drivers.
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CS4525
6.1.8.1 Recommended PWM_SIG Power-Up Sequence for an External PWM
Amplifier
1.
2.
3.
4.
5.
Engage the reset/power-down feature of the external PWM amplifier.
Set the PDnAll bit in the Power Ctrl register to stop the PWM modulators if it is not already set.
Configure the PWM_SIG outputs as desired via the PWMDSel[1:0] bits in the Output Cfg register.
Set the HiZPSig bit in the EQ Config register to activate the PWM_SIG output drivers.
Disengage the reset/power-down feature of the external PWM amplifier if it has an initial transition
delay feature, such as the CS4412A.
WARNING:Releasing the external amplifier from reset/power-down before PWM modulators have started
will cause a DC output on the speakers unless the external amplifier has an initial transition delay feature.
6. Clear the PDnAll bit in the Power Ctrl register to start the PWM modulators.
7. Disengage the reset/power-down feature of the external PWM amplifier if it has not been yet disengaged.
6.1.8.2 Recommended PWM_SIG Power-Down Sequence for an External PWM
Amplifier
1. Mute the PWM_SIG outputs to a 50% duty-cycle by either setting Master Volume to 1111 1111h
(Master Mute) or through use of the HP_DETECT/MUTE input pin as described in the Headphone
Detection & Hardware Mute Input section on page 51.
2. Engage the reset/power-down feature of the external PWM amplifier.
3. Set the PDnAll bit in the Power Ctrl register to disable the PWM modulators and set the PWM_SIG
outputs to a drive a logic ‘0’.
4. Power down the remainder of the system (if applicable).
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CS4525
6.1.8.3
Out
1.
2.
3.
4.
5.
Recommended PWM_SIG Power-Up Sequence for Headphone & Line-
Set the PDnAll bit in the Power Ctrl register to stop the PWM modulators if it is not already set.
Configure the PWM_SIG outputs as desired via the PWMDSel[1:0] bits in the Output Cfg register.
Clear the PDnAll bit in the Power Ctrl register to start the PWM modulators.
Wait 500 ms to allow the internal sample rate converters to achieve lock.
Set the HiZPSig bit in the EQ Config register to activate the PWM_SIG outputs.
6.1.8.4 Recommended PWM_SIG Power-Down Sequence for Headphone &
Line-Out
1. Mute the PWM_SIG outputs to a 50% duty-cycle by either setting Master Volume to 1111 1111h
(Master Mute) or through use of the HP_DETECT/MUTE input pin as described in the Headphone
Detection & Hardware Mute Input section on page 51.
2. Clear the HiZPSig bit in the EQ Config register to put the PWM_SIG output drivers in a high-impedance state.
3. Power down the remainder of the system (if applicable).
Referenced Control
Register Location
PDnAll ................................. “Power Down (PDnAll)” on page 89
HiZPSig ............................... “Hi-Z PWM_SIG Outputs (HiZPSig)” on page 79
PWMDSel[1:0]..................... “PWM Signals Output Data Select (PWMDSel[1:0])” on page 73
Master Volume .................... “Master Volume Control (MVol[7:0])” on page 82
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6.1.8.5
PWM_SIG Logic-Level Output Configurations
Four channel mapping output configurations are supported for the PWM_SIG output pins as shown in
Table 10 below. The configurations support stereo, channel 1 with sub, and channel 2 with sub applications. When disabled, the PWM_SIG pins will continuously drive a logic ‘0’ if the HiZPSig bit is set and will
be held in a high-impedance state if the HiZPSig bit is clear. The configurations are selected by the PWMDSel[1:0] bits in the Output Cfg register. The PWM_SIG2 can be configured to output the sub channel
even if the Bass Manager is not enabled; however, its signal will be muted unless the Bass Manager is
enabled by the BassMgr[2:0] bits. It should be noted that the HiZPSig bit must be set to enable the
PWM_SIG output drivers.
PWMDSel[1:0]
00
01
10
11
PWM_SIG1
Disabled.
Channel 1
Channel 1
Channel 2
PWM_SIG2
Disabled.
Channel 2
Sub Channel
Sub Channel
Table 10. PWM Logic-Level Output Configurations
To allow stereo headphone operation when the PWM logic-level outputs are mapped in a non-stereo output configuration, if the HP_DETECT/MUTE pin is configured for headphone detection (the HP/Mute bit
is set), the PWM logic-level output mapping can be affected by the active state of the headphone detection
input signal. See the Headphone Detection & Hardware Mute Input section on page 51 for more information.
It should be noted that signal on channels 1, 2, and the sub channel are dependent upon the digital sound
processing blocks being used. For instance, if the 2-way crossover is enabled, channel 1 and 2 contain
the 2-way crossover channel A high- and low-pass outputs respectively. For more information, see the
Digital Sound Processing section and Figure 14 on page 29.
Referenced Control
Register Location
PWMDSel[1:0]..................... “PWM Signals Output Data Select (PWMDSel[1:0])” on page 73
HiZPSig ............................... “Hi-Z PWM_SIG Outputs (HiZPSig)” on page 79
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 70
BassMgr[2:0] ....................... “Bass Cross-Over Frequency (BassMgr[2:0])” on page 79
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CS4525
6.1.9
PWM Modulator Configuration
The CS4525 PWM modulators support flexible configuration options designed to simplify system integration. Delays may be inserted between the switching edges on adjacent channels to manage noise, and
the PWM switching frequency can be easily modified to eliminate interference with AM tuners.
6.1.9.1
PWM Channel Delay
The CS4525 includes a PWM output signal delay mechanism. This mechanism allows the PWM switching
edges to be offset between channels as a method of managing switching noise and reducing radiated
emissions.
The OutputDly[3:0] bits in the Output Cfg register are used to adjust the channel delay amount from
0 to 15 SYS_CLK or crystal input clock cycles, whichever is used as the input clock source. The absolute
delay time is calculated by multiplying the setting of the OutputDly[3:0] bits by the period of the input clock
source. By default, no delay is inserted.
When the power outputs are configured for 2-channel full-bridge operation, the OUT3/OUT4 signal pair is
delayed from the OUT1/OUT2 signal pair by the delay amount as shown in Figure 20.
OUT1
OUT2
tchdly
OUT3
OUT4
Figure 20. 2-Channel Full-Bridge PWM Output Delay
When the power outputs are configured for 3-channel (2-channel half-bridge and 1-channel full-bridge)
operation, OUT2 is delayed from OUT1 by the delay amount, and the OUT3/OUT4 pair is delayed from
OUT2 by the delay amount as shown in Figure 21.
OUT1
tch dly
OUT2
tch dly
OUT3
OUT4
Figure 21. 3-Channel PWM Output Delay
The OutputDly[3:0] bits can only be changed when all modulators and associated logic are in the powerdown state by setting the PDnAll bit. Attempts to write these bits while the PDnAll bit is cleared will be
ignored.
Referenced Control
Register Location
OutputDly[3:0] ..................... “Channel Delay Settings (OutputDly[3:0])” on page 73
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CS4525
6.1.9.2
PWM AM Frequency Shift
When using a PWM amplifier in a system containing an AM tuner, it is possible that the PWM switch rate
conflicts with the desired tuning frequency of the AM tuner. To overcome this effect, the CS4525 includes
a PWM switch rate shift feature.
The feature adjusts the PWM switching frequency and quantization levels to remove interference when
the desired tuning frequency of an AM tuner is positioned near a harmonic of the PWM switching rate.
This feature is enabled by setting the FreqShift bit in the Clock Config register. When this feature is enabled, the output switch rate is lowered and the quantization levels are increased as shown in Table 11
below.
Supplied XTAL or
SYS_CLK Frequency
PWM Switch Rate
Quantization Levels
18.432 MHz
329.143 kHz
56
24.576 MHz
341.300 kHz
72
27.000 MHz
375 kHz
72
Table 11. PWM Output Switching Rates and Quantization Levels
The nominal PWM switching frequencies and quantization levels are discussed in “PWM Modulators and
Sample Rate Converters” on page 58.
Referenced Control
Register Location
FreqShift.............................. “AM Frequency Shifting (FreqShift)” on page 70
6.1.10 Headphone Detection & Hardware Mute Input
The CS4525 includes a configurable HP_DETECT/MUTE input pin which can be used as a hardware
mute input or a headphone detection input. The function of this pin is set by the HP/Mute bit in the Clock
Config register.
When configured as a mute input pin, all PWM modulators and the AUX_SDOUT signal will be placed in
a mute state when the pin is active.
When configured as a headphone detect input pin and the HP_DETECT/MUTE input is active, the
PWM_SIG1 and PWM_SIG2 output pins can output audio from channel 1 and channel 2 respectively regardless of the setting of the PWMDSel[1:0] bits. The OUT1 - OUT4 PWM driver outputs will mute by outputting a non-modulated 50% duty cycle signal. While the headphone detect input signal is active, the
channel mixing, 2-way crossover, and bass management features will all be disabled regardless of the
settings of the LChMix[1:0], En2Way, and BassMgr[2:0] bits, respectively. It should be noted that the right
channel’s channel mixing is not affected by the headphone detection input signal and will always output
as dictated by the RChMix[1:0] bits. See “Channel Mixer” on page 30, “2-Way Crossover & Sensitivity
Control” on page 42, and “Bass Management” on page 35 for more information.
When configured as a headphone detect input pin and the HP_DETECT/MUTE input is inactive, the
OUT1 - OUT4 driver outputs will output audio according to the channel mixer and bass manager bits’ settings, and the PWM_SIG output pins will mute by outputting a non-modulated 50% duty cycle.
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CS4525
HiZPSig
Setting
HP/Mute
Setting
0
X
X
X
X
X
X
X
00 (Disabled)
Driven Low
Driven Low
01
Channel 1
Channel 2
10
Channel 1
Mute
11
Channel 2
Mute
01
Channel 1
Channel 2
0
(Mute
Mode)
HP_DETECT BassMgr [2:0] PWMDSel [1:0]
/MUTE Input
Setting
Setting
000
(Disabled)
Not Active
001 through 111
1
1
(Headphone
Mode)
PWM_SIG1
Output
PWM_SIG2
Output
High Impedance High Impedance
10
Channel 1
Sub Channel
11
Channel 2
Sub Channel
Active
X
01, 10, or 11
Mute
Mute
Not Active
X
01, 10, or 11
Mute
Mute
01
Channel 1*
Channel 2**
Active
000
(Disabled)
10
Channel 1*
Mute
11
Channel 2**
Mute
001 through 111
01, 10, or 11
Channel 1*
Channel 2**
*Signals denoted with one asterisk do not have Bass Manager, 2-Way Crossover, or Channel Mix applied.
**Signals denoted with two asterisks do not have Bass Manager or 2-Way Crossover applied.
Table 12. Output of PWM_SIG Outputs
Table 12 describes the exact output of the PWM_SIG output pins based on the input to the
HP_DETECT/MUTE pin and the settings of the HiZPSig, HP/Mute, BassMgr[2:0], and PWMDSel[1:0]
bits. In all configurations, the active logic input level is determined by the HP/MutePol bit.
Referenced Control
Register Location
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 70
HP/MutePol ......................... “HP_Detect/Mute Pin Active Logic Level (HP/MutePol)” on page 70
PWMDSel[1:0]..................... “PWM Signals Output Data Select (PWMDSel[1:0])” on page 73
LChMix[1:0] ......................... “Left Channel Mixer (LChMix[1:0])” on page 76
RChMix[1:0] ........................ “Right Channel Mixer (RChMix[1:0])” on page 76
En2Way............................... “Enable 2-Way Crossover (En2Way)” on page 81
BassMgr[2:0] ....................... “Bass Cross-Over Frequency (BassMgr[2:0])” on page 79
HiZPSig ............................... “Hi-Z PWM_SIG Outputs (HiZPSig)” on page 79
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CS4525
6.1.11
Interrupt Reporting
The CS4525 has comprehensive interrupt reporting capabilities. Many conditions including SRC lock,
ADC overflow, digital data path overflow, and amplifier errors can cause an interrupt.
The INT output pin is intended to drive an interrupt input pin on a host microcontroller. The INT pin is an
open-drain active-low output and requires an external pull-up for proper operation.
If an interrupt source is un-masked, its occurrence will cause the interrupt output pin to become active. To
enhance flexibility, each interrupt source may be masked such that its occurrence does not cause the interrupt output pin to become active. This masking function is accomplished by clearing an interrupt’s respective mask bit located in the 4 LSB’s of the Interrupt register.
When a specific interrupt condition occurs, its respective bit located in the 4 MSB’s of the Interrupt register
will be set to indicate that a change has occurred for the associated interrupt type. When the interrupt register is read, the contents of the 4 MSB’s will be cleared. The Int Status register may then be read to determine the current state of the interrupt source.
For specific information regarding interrupt types and reporting, see the Interrupt, Int Status and Amp Error register descriptions.
Referenced Control
Register Location
Interrupt Register ................ “Interrupt (Address 60h)” on page 89
Int Status Register............... “Interrupt Status (Address 61h) - Read Only” on page 92
Amp Error Register ............. “Amplifier Error Status (Address 62h) - Read Only” on page 93
6.1.12 Automatic Power Stage Shut-Down
To prevent permanent damage, the CS4525 will automatically shut down its internal PWM power output
stages when a thermal error, PWM power output over-current error, or VP under-voltage condition occurs.
In the shut-down state, all digital functions of the device will operate as normal, however the PWM power
output pins become high-impedance.
The levels of the over-current error, thermal error, and VP under-voltage trigger points are listed in the
PWM Power Output Characteristics table on page 20. Automatic shut-down will occur whenever any of
these preset thresholds are crossed.
Once in the shut-down state, each powered PWM outputs will remain as high-impedance and will not resume normal operation until either the PDnAll bit or the PDnOutX bit for the channel in error is set and
then cleared.
If the AutoRetry bit is set, the CS4525 will attempt to automatically resume power output operation after
an over-current error is encountered and before entering the shut-down state. With the AutoRetry function
enabled, the CS4525 will place the PWM power outputs in a high-impedance state upon the sensing of
an over-current condition, wait approximately 85 ms, and then re-engage the power outputs in an attempt
to resume normal operation. If another over-current condition is immediately detected, the PWM power
outputs will again be placed in a high-impedance state before retrying to resume normal operation a second time. It will continue this sequence for a maximum of five attempts. After the fifth unsuccessful attempt, the outputs will remain in a high-impedance state until the PDnAll bit is set and then cleared.
Referenced Control
Register Location
AutoRetry ............................ “Automatic Power Stage Retry (AutoRetry)” on page 88
PDnAll ................................. “Power Down (PDnAll)” on page 89
PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 89
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CS4525
6.2
Hardware Mode
A limited feature set is available when the CS4525 powers up in hardware mode. The available features are
described in the following sections. All device configuration is achieved via hardware control input pins.
6.2.1
System Clocking
In hardware mode, the CS4525 must be clocked by a stable external clock source input on the SYS_CLK
pin. This input clock is used to synchronize the input serial audio signals with the internal clock domain
and to clock the internal digital processing, sample-rate converter, and PWM modulators. It is also used
to determine the sample rate of the serial audio input signals in order to automatically configure the various internal filter coefficients.
To ensure proper operation, the CS4525 must be informed of the nominal frequency of the supplied
SYS_CLK signal via the ClkFreq0 hardware control pin. This pin must be set to the appropriate level before the RST signal is released to initiate a power-up sequence. The ClkFreq1 pin must always be connected to DGND. The nominal clock frequencies indicated by the state of the ClkFreq0 pin are shown in
Table 13 below. See the SYS_CLK Switching Specifications table on page 23 for complete input frequency range specifications.
ClkFreq1
Low
Low
ClkFreq0
Low
High
Nominal SYS_CLK Frequency
18.432 MHz
24.576 MHz
Table 13. SYS_CLK Frequency Selection
WARNING: The SYS_CLK signal must never be removed or stopped while the RST pin is high and any
of the power output stages are connected to a load. Doing so may result in permanent damage to the
CS4525 and connected transducers.
Figure 22 below demonstrates a typical clocking configuration using the SYS_CLK input.
Clock
Clock_In
SYS_CLK
DSP
CS4525
XTI
Reset_Out
RST
XTO
Figure 22. Typical SYS_CLK Input Clocking Configuration
6.2.2
Power-Up and Power-Down
The CS4525 will remain in a completely powered-down state until the RST pin is brought high.
6.2.2.1
Power-Up Sequence
1. Apply the SYS_CLK signal.
2. Hold RST low until the power supplies and the input SYS_CLK signal are stable.
3. Bring RST high.
Hardware mode will be entered after approximately 10 ms.
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CS4525
6.2.2.2
Power-Down Sequence
1. Bring MUTE low to mute the device’s outputs and minimize audible pops.
2. Bring RST low to halt the operation of the device.
The device’s power consumption will be brought to an absolute minimum.
3. The SYS_CLK signal may now be removed. See section 6.2.1 on page 54 for more information.
4. Remove power.
6.2.3
Input Source Selection
The CS4525 can accept analog or digital audio input signals. Digital audio input signals are supplied
through the serial audio input port as outlined in “Serial Audio Interfaces” on page 62. Analog audio input
signals are supplied through the internal ADC as outlined in “Analog Inputs” on page 61. The input source
is selected by the ADC/SP pin as shown in Table 14 below and can be changed at any time without causing any audible pops or clicks.
ADC/SP
Selected Input Source
Low
Digital Audio Inputs (Serial Port)
High
Analog Audio Inputs (ADC)
Table 14. Input Source Selection
In hardware mode, the serial audio input port supports both I²S and left-justified formats. The serial audio
interface format is selected by the I2S/LJ pin as shown in Table 15 below.
I2S/LJ
Selected Serial Audio Interface Format
Low
Left-Justified
High
I²S
Table 15. Serial Audio Interface Format Selection
6.2.4
PWM Channel Delay
In hardware mode, the CS4525 offsets the PWM switching edges between channels as a method of managing switching noise and reducing radiated emissions.
The OUT3/OUT4 signal pair is delayed from the OUT1/OUT2 signal pair by 4 SYS_CLK cycles as shown
in Figure 23 below. The absolute delay time is calculated by multiplying the period SYS_CLK by 4.
OUT1
OUT2
4 x TSYS_CLK
OUT3
OUT4
Figure 23. Hardware Mode PWM Output Delay
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CS4525
6.2.5
Digital Signal Flow
In hardware mode, the CS4525 operates as a 2-channel full-bridge PWM amplifier with analog or digital
inputs. Both the PWM outputs and the auxiliary serial outputs are unavailable in hardware mode. To protect against over-temperature conditions, thermal foldback is included for the internal power stages.
The digital signal flow is shown in Figure 24 below.
MUTE
Serial Audio
Clocks & Data
Serial Audio
Input Port
+3dB
Sample
Rate
Converter
PWM
Modulator
Sample
Rate
Converter
PWM
Modulator
Mute
Multi-Bit
∆Σ ADC
High-Pass
Stereo
Analog In
+3dB
Thermal Foldback
ADC/SP
I²S/LJ
Thermal Foldback
EN_TFB
Gate
Drive
Power
Stage
Gate
Drive
Power
Stage
Gate
Drive
Power
Stage
Gate
Drive
Power
Stage
Temp & Current
Sense
Left
Full-Bridge
Amplifier
Output
Right
Full-Bridge
Amplifier
Output
TWR
ERROC
ERRUVTE
Figure 24. Hardware Mode Digital Signal Flow
6.2.5.1
High-Pass Filter
The CS4525 includes a high-pass filter at the beginning of the digital signal processing chain to remove
any DC content from the input signal prior to the remaining internal digital signal processing blocks. The
high-pass filter operates by continuously subtracting a measure of the DC offset from the input signal; it
is always enabled.
6.2.5.2
Mute Control
The CS4525 includes a dedicated MUTE input pin. When low, the PWM outputs will output silence as
modulated signal. When high, the selected input source will be presented at the amplifier outputs.
It should be noted that the auto-mute, soft-ramp, and zero-crossing detection features are active in hardware mode.
6.2.5.3
Warning and Error Reporting
The CS4525 is capable of reporting various error and warning conditions on its TWR, ERROC, and ERRUVTE pins.
•
The TWR pin indicates the presence of a thermal warning condition. When active concurrently with the
ERRUVTE pin, indicates a thermal error condition.
•
The ERROC pin indicates the presence of an over-current condition on one or both of the output channels.
•
The ERRUVTE pin indicates the presence of a VP undervoltage condition. When active concurrently
with the TWR pin, indicates a thermal error condition.
The trigger point for each warning and error condition is defined in the PWM Power Output Characteristics
table on page 20. Each pin implements an active-low open-drain driver and requires an external pull-up
for proper operation.
56
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CS4525
6.2.6
Thermal Foldback
In hardware mode, the CS4525 implements a thermal foldback feature to guard against damaging thermal
overload conditions. The thermal foldback feature begins limiting the volume of the digital audio input to
the amplifier stage as the junction temperatures rise above the maximum safe operating range specified
by the thermal warning trigger point listed in the PWM Power Output Characteristics table on page 20.
This effectively limits the output power capability of the device, thereby allowing the temperature to reduce
to acceptable levels without fully interrupting operation. As the device cools, the applied attenuation is
gradually released until a new thermal equilibrium is reached or all applied attenuation has been released
thereby allowing the device to again achieve its full output power capability.
Attenuation applied due to thermal foldback reduces the audio output level in a linear manner. Figure 18
below demonstrates the foldback process.
Foldback Attack Delay
Approximately 2 sec.
tdelay
tdelay
tdelay
tdelay
tdelay
2
2
2
Thermal Warning
Threshold
1
1
2
3
1
When the junction temperature crosses the thermal warning threshold, the foldback attack delay timer is started.
2
When the foldback attack delay timer reaches tdelay seconds, the junction temperature is checked. If it is above the
thermal warning threshold, the output volume level is lowered by 0.5 dB and the foldback attack timer is restarted.
The junction temperature is checked after each foldback attack timer timeout, and if necessary, the output volume
level is lowered accordingly.
If the junction temperature is found to be below the thermal warning threshold, the foldback attack timer is
restarted once again, but the output volume level is not altered. The foldback algorithm then proceeds to step 3.
3
The junction temperature is checked once again after the next foldback attack timer timeout. If is has remained
below the thermal warning threshold since the last check, the device will begin to release any attenuation applied
as a result of the foldback event.
If the junction temperature crosses the thermal warning threshold again, the foldback algorithm will once again
enter step 1.
Figure 25. Foldback Process
Thermal warning conditions will only affect the foldback algorithm and cause attenuation to be applied if
enabled by the EN_TFB pin as shown in Table 16 below.
EN_TFB
Selected Thermal Foldback Enable State
Low
High
Thermal foldback disabled.
Thermal foldback enabled.
Table 16. Thermal Foldback Enable Selection
DS726PP3
57
CS4525
6.2.7
Automatic Power Stage Shut-Down
To protect itself from permanent damage, the CS4525 will automatically shut down its internal PWM power output stages when a thermal error, PWM power output over-current error, or VP under-voltage condition occurs. In the shut-down state, all digital functions of the device will operate as normal, however the
PWM power output pins become high-impedance.
The levels of the over-current error, thermal error, and VP under-voltage trigger points are listed in the
PWM Power Output Characteristics table on page 20. Shut-down will occur automatically whenever the
preset thresholds for thermal error or under-voltage are crossed.
When the over-current threshold is crossed, the CS4525 will attempt to automatically resume power output operation after an over-current error is encountered and before placing its PWM power outputs in the
shut-down state. Upon the detection of an over-current condition, the CS4525 will place the PWM power
outputs in a high-impedance state, wait approximately 85 ms, and then re-engage the power outputs in
an attempt to resume normal operation. If another over-current condition is immediately detected, the
PWM power outputs will again be placed in a high-impedance state before retrying to resume normal operation a second time. It will continue this sequence for a maximum of five attempts. After the fifth unsuccessful attempt, the outputs will remain in the high-impedance shut-down state.
Once in the shut-down state, the RST signal must be toggled low and then high to resume normal device
operation.
6.3
PWM Modulators and Sample Rate Converters
The CS4525 includes three PWM modulators and three corresponding sample rate converters, each
clocked from the external crystal or system clock applied at power-up. All three modulator and sample rate
converter pairs are available in software mode (see Figure 14 on page 29), and two pairs are used in hardware mode (see Figure 24 on page 56).
One of the characteristics of a PWM modulator is that the frequency content of the out-of-band noise generated is dependent on the PWM switching frequency. As the power stage external LC and snubber filter
component values are used to attenuate this out-of band energy, their component values are also based on
this switching frequency.
To easily accommodate input sample rates ranging from 32 kHz to 96 kHz without requiring the adjustment
of output filter component values, the CS4525 utilizes a sample rate converter (SRC) to keep the PWM
switching frequency fixed regardless of the input sample rate. The SRC operates by upsampling the variable
input sample rate to a fixed output switching rate, typically 384 kHz for most audio applications. Table 17
below shows the PWM output switching rate and quantization levels as a function of the supplied external
crystal or system clock.
Additionally, as the output of the SRC is clocked from a very stable crystal or oscillator, the SRC also allows
the PWM modulator output to be independent of the input serial audio clock jitter. This results in very low
jitter PWM output and higher dynamic range.
Supplied XTAL or
SYS_CLK Frequency
PWM Switch Rate
Quantization Levels
18.432 MHz
384 kHz
48
24.576 MHz
384 kHz
64
27.000 MHz
421.875 kHz
64
Table 17. PWM Output Switching Rates and Quantization Levels
58
DS726PP3
CS4525
6.4
Output Filters
The output filter configuration of the CS4525 can greatly affect device performance. These components reduce radiated EMI, protect the output transistors of the device, attenuate the high frequency content of the
output signal, and, in the half bridge configuration, block DC current from reaching the loudspeaker.
6.4.1
Half-Bridge Output Filter
Figure 26 shows the output filter for a half-bridge configuration. A transient voltage suppression circuit is
implemented as an RC snubber network comprised of a resistor Rs (5.6 Ω, 1/8 W) and a capacitor Cs
(680 pF). This should be placed as close as possible to the corresponding output pin. This circuit decreases the slew rate of the output signal and reduces high frequency ringing which can lead to increased EMI.
The Schottky diodes protect the body diodes of the output devices by conducting load current during
switching transitions; these diodes must be present to ensure proper device operation.
VP
CS4525
D1*
C2
L1
OUTx
Cs
680 pF
Rs
5.6 Ω
D2*
* ROHM RB160 M-30
or equivalent
C1
Figure 26. Output Filter - Half-Bridge
The inductor L1 and capacitor C1 form a low-pass filter to remove high frequency switching content from
the output signal. These values combine with the nominal load impedance of the speaker to set the cutoff frequency of the filter. Table 18 shows the component values for L1 and C1 based on nominal speaker
impedance for a corner frequency of approximately 35 kHz (-3 dB).
Load
L1
C1
4Ω
6Ω
8Ω
22 µH
33 µH
47 µH
1.0 µF
0.68 µF
0.47 µF
Table 18. Low-Pass Filter Components - Half-Bridge
C2 serves to block DC from the output. Table 19 shows the component values for C2 based on desired
corner frequency (-3 dB) and nominal speaker impedances of 4 Ω, 6 Ω, and 8 Ω. This capacitor should be
chosen to have a ripple current rating higher than the amount of current that will pass through it.
Load
Corner Frequency
C2
4Ω
40 Hz
58 Hz
120 Hz
39 Hz
68 Hz
120 Hz
42 Hz
60 Hz
110 Hz
1000 µF
680 µF
330 µF
680 µF
390 µF
220 µF
470 µF
330 µF
180 µF
6Ω
8Ω
Table 19. DC-Blocking Capacitors Values - Half-Bridge
DS726PP3
59
CS4525
6.4.2
Full-Bridge Output Filter (Stereo or Parallel)
Figure 27 shows the output filter for stereo full-bridge and parallel full-bridge output configurations. Transient voltage suppression circuits are implemented as a RC snubber networks comprised of resistors Rs
(5.6 Ω, 1/8 W) and capacitors Cs (680 pF). These should be placed as close as possible to the corresponding output pin. These circuits decrease the slew rate of the output signal and reduce high frequency
ringing which can lead to increased EMI. The Schottky diodes protect the body diodes of the output devices by conducting load current during switching transitions; these diodes must be present to ensure
proper device operation.
VP
CS4525
D1*
L1
OUT+
Cs
680 pF
Rs
5.6 Ω
D2*
* ROHM RB160 M-30
or equivalent
C1
VP
D3*
L2
OUTCs
680 pF
D4*
Rs
5.6 Ω
Figure 27. Output Filter - Full-Bridge
The inductors L1 and L2 along with capacitor C1 form the low-pass filter. These values combine with the
nominal load impedance of the speaker to set the cut-off frequency of the filter. Table 20 shows the component values based on nominal speaker impedance for a corner frequency of approximately 35 kHz
(-3 dB).
Load
L1, L2
C1
4Ω
6Ω
8Ω
10 µH
15 µH
22 µH
1.0 µF
0.47 µF
0.47 µF
Table 20. Low-Pass Filter Components - Full-Bridge
60
DS726PP3
CS4525
6.5
Analog Inputs
Very few components are required to interface between the audio source and the CS4525’s analog inputs,
AINL and AINR. A single order passive low-pass filter is recommended to prevent high-frequency content
from aliasing into the audio band due to the analog-to-digital conversion process. Also, a DC-blocking capacitor is required as the CS4525’s analog inputs are internally biased to VQ.
The recommended analog input circuit is shown in Figure 28 below will accommodate full-scale input voltages as defined in the Analog Input Characteristics table on page 19. This circuit provides the necessary
high-frequency filtering with a first-order passive low-pass filter that has less than 0.05 dB of attenuation at
24 kHz. It also includes a DC blocking capacitor to accommodate the analog input pins’ bias level.
CS4525
1 µF
Left Input
100 kΩ
365 Ω
AINL
1800 pF
C0G
1 µF
Right Input
100 kΩ
365 Ω
AINR
1800 pF
C0G
Figure 28. Recommended Unity Gain Input Filter
To interface 2 VRMS input signals with the CS4525’s analog inputs, an external resistor divider is required.
Figure 29 shows the recommended input circuit for 2 VRMS inputs. It includes a -8.4 dB passive attenuator
to condition the input signal for the CS4525’s full-scale input voltage, a first-order passive low-pass filter that
has less than 0.05 dB of attenuation at 24 kHz, and a DC blocking capacitor to accommodate for the analog
input pins’ bias level. The passive attenuator network should be placed as close as possible to the CS4525’s
analog input pins to reduce the potential for noise and signal coupling into the analog input traces.
CS4525
Left Input
8.06 kΩ
5.62 kΩ
Right Input
8.06 kΩ
5.62 kΩ
1 µF
AINL
100 pF
C0G
1 µF
AINR
100 pF
C0G
Figure 29. Recommended 2 VRMS Input Filter
It should be noted that the external DC blocking capacitor forms a high-pass filter with the CS4525’s input
impedance. Both filters shown above have less than 0.2 dB attenuation at 20 Hz due to this effect. Increasing the value of this capacitor will lower this high-pass corner frequency, and decreasing it’s value will increase the corner frequency.
DS726PP3
61
CS4525
6.6
Serial Audio Interfaces
The CS4525 interfaces to external digital audio devices via the serial audio input port and the auxiliary/delay
serial ports.
The serial audio input port provides support for I²S, Left-Justified and Right-Justified data formats and operates in slave mode only, with LRCK and SCLK as inputs. The input LRCK signal must be equal to the
sample rate, Fs and must be synchronous to the serial bit clock, SCLK, which is used to sample the data
bits.
The auxiliary/delay serial port (available in software mode only) supports I²S and Left-Justified data formats
and operates in master mode only, with AUX_LRCK and AUX_SCLK as outputs.
Each of the supported formats is described in detail in sections 6.6.1 - 6.6.3 below. Please refer to the Serial
Audio Input Port Switching Specifications and AUX Serial Audio I/O Port Switching Specifications on
page 21 and page 22 (respectively) for the precise timing and tolerances of each signal.
For additional information, application note AN282 presents a tutorial of the 2-channel serial audio interface.
AN282 can be downloaded from the Cirrus Logic web site at http://www.cirrus.com.
6.6.1
I²S Data Format
In I²S format, data is received most significant bit first one SCLK delay after the transition of LRCK and is
valid on the rising edge of SCLK. The left channel data is presented when LRCK is low; the right channel
data is presented when LRCK is high.
Left Channel
LRCK
Right Channel
SCLK
SDIN
MSB
-1 -2 -3 -4 -5
+5 +4 +3 +2 +1
LSB
MSB
-1 -2 -3 -4
+5 +4 +3 +2 +1 LSB
Figure 30. I²S Serial Audio Formats
6.6.2
Left-Justified Data Format
In Left-Justified format, data is received most significant bit first on the first SCLK after a LRCK transition
and is valid on the rising edge of SCLK. The left channel data is presented when LRCK is high and the
right channel data is presented when LRCK is low.
LRCK
Left Channel
Right Channel
SCLK
SDIN
MSB
-1 -2 -3 -4 -5
+5 +4 +3 +2 +1
LSB
MSB
-1 -2 -3 -4
+5 +4 +3 +2 +1
LSB
Figure 31. Left-Justified Serial Audio Formats
62
DS726PP3
CS4525
6.6.3
Right-Justified Data Format
In Right-Justified format, data is received most significant bit first and with the least significant bit presented on the last SCLK before the LRCK transition and is valid on the rising edge of SCLK. For the RightJustified format, the left channel data is presented when LRCK is high and the right channel data is presented when LRCK is low. 16, 18, 20, and 24 bits per sample are supported.
LRCK
Right Channel
Left Channel
SCLK
SDIN
15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
15 14 13 12 11 10 9
8
7
6 5
4
3
2
1
0
Figure 32. Right-Justified Serial Audio Formats
6.7
Integrated VD Regulator
The CS4525 includes two internal linear regulators, one from the VD supply voltage to provide a fixed 2.5 V
supply to its internal digital blocks, and another from the VD supply voltage to provide a fixed 2.5 V supply
to its internal analog blocks. The LVD pin must be set to indicate the voltage present on the VD pin as shown
in Table 21 below.
VD
Connection
5 V Supply
3.3 V Supply
2.5 V Supply
VD_REG
Connection
Bypass Capacitors Only
Bypass Capacitors Only
VD and Bypass Capacitors
VA_REG
Connection
Bypass Capacitors Only
Bypass Capacitors Only
VD and Bypass Capacitors
LVD
Connection
VD
DGND
DGND
SelectVD Bit Setting
Software Mode Only
‘1’ - Default
‘1’ - Default
‘0’
Table 21. Power Supply Configuration and Settings
The output of the digital regulator is presented on the VD_REG pin and may be used to provide an external
device with up to 3 mA of current at its nominal output voltage of 2.5 V. The output of the analog regulator
is presented on the VA_REG pin and must only be connected to the bypass capacitors as shown in the typical connection diagrams.
If a nominal supply voltage of 2.5 V is used as the VD supply (see the Recommended Operating Conditions
table on page 18), the VD, VD_REG, and VA_REG pins must all be connected to the VD supply source. In
this configuration, the internal regulators are bypassed and the external supply source is used to directly
drive the internal digital and analog sections.
Referenced Control
Register Location
SelectVD ............................. “Select VD Level (SelectVD)” on page 88
DS726PP3
63
CS4525
6.8
I²C Control Port Description and Timing
The control port is used to access the registers allowing the CS4525 to be configured for the desired operational modes and formats. The operation of the control port may be completely asynchronous with respect
to the audio sample serial port. However, to avoid potential interference problems, the control port pins
should remain static if no operation is required. The control port operates in I²C Mode, with the CS4525 acting as a slave device.
SDA is a bidirectional data line. Data is clocked into and out of the part by the clock, SCL. A 47 kΩ pull-up
or pull-down on the AUX_LRCK/AD0 pin will set AD0, the least significant bit of the device address. A pullup to VD will set AD0 to ‘1’ and a pull-down to DGND will set AD0 to ‘0’. The state of AUX_LRCK/AD0 is
sensed, and AD0 is set upon the release of RESET.
The signal timings for a read and write cycle are shown in Figure 33 and Figure 34. A Start condition is defined as a falling transition of SDA while the clock is high. A Stop condition is a rising transition while the
clock is high. All other transitions of SDA occur while the clock is low. The first byte sent to the CS4525 after
a Start condition consists of a 7 bit device address field and a R/W bit (high for a read, low for a write). The
upper 6 bits of the 7-bit address field are fixed at 100101. To communicate with a CS4525, the device address field, which is the first byte sent to the CS4525, should match 100101 followed by the setting of AD0.
The eighth bit of the address is the R/W bit. If the operation is a write, the next byte is the memory address
pointer (MAP) which selects the register to be read or written. If the operation is a read, the contents of the
register pointed to by the MAP will be output. Setting the auto increment bit in MAP allows successive reads
or writes of consecutive registers. Each byte is separated by an acknowledge bit. The ACK bit is output from
the CS4525 after each input byte is read, and is input to the CS4525 from the microcontroller after each
transmitted byte.
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18
19
24 25 26 27 28
SCL
CHIP ADDRESS (WRITE)
1
SDA
0
0
1
0
1
AD0
MAP BYTE
0
6
INCR
5
4
3
DATA +1
DATA
2
1
ACK
0
7
6
1
ACK
0
7
6
1
DATA +n
0
7
6
1
0
ACK
ACK
STOP
START
Figure 33. Control Port Timing, I²C Write
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
16
17 18
19
20 21 22 23 24 25 26 27 28
SCL
CHIP ADDRESS (WRITE)
SDA
1
0
0
1
0 1 AD0 0
INCR
ACK
START
STOP
MAP BYTE
6
5
4
3
2
1
CHIP ADDRESS (READ)
1
0
ACK
0
0
1
0
DATA
1 AD0 1
7
ACK
START
DATA +1
0
7
ACK
0
DATA + n
7
0
NO
ACK
STOP
Figure 34. Control Port Timing, I²C Read
Since the read operation can not set the MAP, an aborted write operation is used as a preamble. As shown
in Figure 34, the write operation is aborted after the acknowledge for the MAP byte by sending a stop condition. The following pseudocode illustrates an aborted write operation followed by a read operation.
Send start condition.
Send 100101x0 (device address and write operation).
Receive acknowledge bit.
Send MAP byte, auto increment off.
Receive acknowledge bit.
Send stop condition, aborting write. (Optional.)
Send start condition.
Send 100101x1(device address and read operation).
64
DS726PP3
CS4525
Receive acknowledge bit.
Receive byte, contents of selected register.
Send acknowledge bit.
Send stop condition. (Optional.)
7. PCB LAYOUT CONSIDERATIONS
7.1
Power Supply, Grounding
The CS4525 requires careful attention to power supply and grounding arrangements if its potential performance is to be realized. Extensive use of power and ground planes, ground plane fill in unused areas and
surface mount decoupling capacitors are recommended. Decoupling capacitors should be as close to the
pins of the CS4525 as possible. The lowest value ceramic capacitor should be closest to the pin and should
be mounted on the same side of the board as the CS4525 to minimize inductance effects. All signals, especially clocks, should be kept away from the FILT+ and VQ pins in order to avoid unwanted coupling into
the modulators. The FILT+ and VQ decoupling capacitors, particularly the 0.1 µF, must be positioned to
minimize the electrical path from FILT+ and AGND. The CRD4525 reference design demonstrates the optimum layout and power supply arrangements.
7.2
Output Filter Layout
The CS4525 also requires careful attention to the layout of the output filter. This will ensure optimum device
performance and EMI standards compliance. The CRD4525 customer reference designs incorporate many
techniques and practices that should be followed in any design using this device and should be referred to
as a guide during the PCB design process. The output components should be placed as close as possible
to the device with the following priority listed from the CS4525 outward:
1. The small value VP bypass capacitors must be placed on the same layer as the CS4525 immediately
adjacent to the each of the device’s VP pins.
2. Following the small value VP bypass capacitors, the RC snubber circuits must be placed on the same
layer as the CS4525 and as close to the device's output pins as possible.
3. The Schottky protection diodes must be placed on the same layer as the CS4525 adjacent to and
immediately following the RC snubber components.
4. The LC output filters must be placed on the same layer as the CS4525 adjacent to and immediately
following the Schottky protection diodes, keeping the trace length as short as possible to reduce
radiated EMI.
Avoid any breaks in the ground and power planes beneath high-frequency switching signals. Parasitic inductances should be reduced by the use of multiple smaller vias instead of a single large via when connecting a output filter and power supply bypass capacitors to a ground or power plane. In addition to improving
the thermal performance of the design, filling all unused areas with copper will help reduce both EMI emissions and coupling between adjacent signals. Finally, 150 pF capacitors should be placed directly across
the speaker outputs to shunt remaining high frequency energy prior to the output cables. Any proposed layout should be directly compared to the CRD4525 customer reference designs before manufacture.
7.3
QFN Thermal Pad
The underside of the QFN package reveals a large metal pad that serves as a thermal relief to provide for
maximum heat dissipation. This pad must mate with an equally dimensioned copper pad on the PCB and
must be electrically connected to ground. A series of thermal vias should be used to connect this copper
pad to one or more larger ground planes on other PCB layers. The CRD4525 reference design demonstrates the optimum thermal pad and via configuration.
DS726PP3
65
CS4525
8. REGISTER QUICK REFERENCE
This table shows the register names and their associated default values.
Adr
Name
7
6
5
4
3
2
1
01h Clock Config EnSysClk DivSysClk
ClkFreq1
ClkFreq0 HP/MutePol HP/Mute
PhaseShift
page 69
1
0
0
1
0
0
0
EnAnHPF
Reserved
SPRate1
SPRate0
DIF2
DIF1
02h Input Config
ADC/SP
page 71
0
1
0
x
x
0
0
03h Aux Config
EnAuxPort DlyPortCfg1 DlyPortCfg0 AuxI²S/LJ RChDSel1 RChDSel0 LChDSel1
page 72
0
0
0
0
0
1
0
04h Output Cfg
OutputCfg1 OutputCfg0 PWMDSel1 PWMDSel0 OutputDly3 OutputDly2 OutputDly1
page 73
0
0
0
0
0
0
0
05h Foldback Cfg SelectVP
EnTherm
LockAdj
AttackDly1 AttackDly0
EnFloor
RmpSpd1
page 74
1
0
0
0
1
0
1
06h Mixer Config PreScale2 PreScale1 PreScale0 Reserved
RChMix1
RChMix0
LChMix1
page 75
0
0
0
0
0
0
0
07h Tone Config
DeEmph
Loudness EnDigHPF
TrebFc1
TrebFc0
BassFc1
BassFc0
page 76
0
0
0
0
0
0
1
08h Tone Control
Treble3
Treble2
Treble1
Treble0
Bass3
Bass2
Bass1
page 78
1
0
0
0
1
0
0
BassMgr2 BassMgr1 BassMgr0
Reserved EnChBPEq
09h EQ Config
Freeze
HiZPSig
page 78
0
0
0
0
0
0
0
0Ah
MSB
.............................................................................................................................
BiQuad 1
0Bh
MSB-8
.............................................................................................................................
A1 Coeff
0Ch
LSB+7
.............................................................................................................................
0Dh
MSB
.............................................................................................................................
BiQuad 1
0Eh
MSB-8
.............................................................................................................................
A2 Coeff
0Fh
LSB+7
.............................................................................................................................
10h
MSB
.............................................................................................................................
BiQuad 1
11h
MSB-8
.............................................................................................................................
B0 Coeff
12h
LSB+7
.............................................................................................................................
13h
MSB
.............................................................................................................................
BiQuad 1
14h
MSB-8
.............................................................................................................................
B1 Coeff
15h
LSB+7
.............................................................................................................................
16h
MSB
.............................................................................................................................
BiQuad 1
17h
MSB-8
.............................................................................................................................
B2 Coeff
18h
LSB+7
.............................................................................................................................
19h
MSB
.............................................................................................................................
BiQuad 2
1Ah
MSB-8
.............................................................................................................................
A1 Coeff
1Bh
LSB+7
.............................................................................................................................
1Ch
MSB
.............................................................................................................................
BiQuad 2
1Dh
MSB-8
.............................................................................................................................
A2 Coeff
1Eh
LSB+7
.............................................................................................................................
1Fh
MSB
.............................................................................................................................
BiQuad 2
20h
MSB-8
.............................................................................................................................
B0 Coeff
21h
LSB+7
.............................................................................................................................
22h
MSB
.............................................................................................................................
BiQuad 2
23h
MSB-8
.............................................................................................................................
B1 Coeff
24h
LSB+7
.............................................................................................................................
66
0
FreqShift
0
DIF0
0
LChDSel0
0
OutputDly0
0
RmpSpd0
1
LChMix0
0
EnToneCtrl
0
Bass0
0
EnChAPEq
0
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
DS726PP3
CS4525
Adr
25h
26h
27h
28h
29h
2Ah
2Bh
2Ch
2Dh
2Eh
2Fh
30h
31h
32h
33h
34h
35h
36h
37h
38h
39h
3Ah
3Bh
3Ch
3Dh
3Eh
3Fh
40h
41h
42h
43h
44h
45h
46h
47h
48h
49h
4Ah
4Bh
4Ch
4Dh
4Eh
4Fh
50h
51h
52h
53h
54h
Name
BiQuad 2
B2 Coeff
BiQuad 3
A1 Coeff
BiQuad 3
A2 Coeff
BiQuad 3
B0 Coeff
BiQuad 3
B1 Coeff
BiQuad 3
B2 Coeff
BiQuad 4
A1 Coeff
BiQuad 4
A2 Coeff
BiQuad 4
B0 Coeff
BiQuad 4
B1 Coeff
BiQuad 4
B2 Coeff
BiQuad 5
A1 Coeff
BiQuad 5
A2 Coeff
BiQuad 5
B0 Coeff
BiQuad 5
B1 Coeff
BiQuad 5
B2 Coeff
DS726PP3
7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
MSB
MSB-8
LSB+7
6
5
4
3
2
1
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0
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
MSB-7
LSB+8
LSB
67
CS4525
Adr
Name
55h Volume Cfg
page 80
56h Sensitivity
page 81
57h Master Vol
page 82
58h Ch A Vol
page 83
59h Ch B Vol
page 83
5Ah Sub Vol
page 83
5Bh Mute Control
page 84
5Ch Limiter Cfg 1
page 85
5Dh Limiter Cfg 2
page 87
5Eh Limiter Cfg 3
page 87
5Fh Power Ctrl
page 88
60h Interrupt
page 89
61h Int Status
page 92
62h Amp Error
page 93
63h Device ID
page 94
68
7
6
SZCMode1 SZCMode0
1
0
LowPass3 LowPass2
0
0
MVol7
MVol6
0
0
ChAVol7
ChAVol6
0
0
ChBVol7
ChBVol6
0
0
SubVol7
SubVol6
0
0
InvADC
InvSub
0
0
Max2
Max1
0
0
Reserved
Reserved
0
0
EnThLim
Reserved
0
0
AutoRetry EnOCProt
1
1
SRCLock
ADCOvfl
x
x
SRCLockSt ADCOvflSt
x
x
OverCurr4 OverCurr3
x
x
DeviceID4 DeviceID3
1
1
5
4
Mute50/50
0
LowPass1
0
MVol5
1
ChAVol5
1
ChBVol5
1
SubVol5
1
InvCh2
0
Max0
0
RRate5
1
ARate5
0
SelectVD
1
ChOvfl
x
SubOvflSt
x
OverCurr2
x
DeviceID2
1
AutoMute
1
LowPass0
0
MVol4
0
ChAVol4
1
ChBVol4
1
SubVol4
1
InvCh1
0
Min2
0
RRate4
1
ARate4
0
PDnADC
1
AmpErr
x
Ch2OvflSt
x
OverCurr1
x
DeviceID1
1
3
2
1
0
En2Way 2WayFreq2 2WayFreq1 2WayFreq0
0
0
0
0
HighPass3 HighPass2 HighPass1 HighPass0
0
0
0
0
MVol3
MVol2
MVol1
MVol0
1
0
1
0
ChAVol3
ChAVol2
ChAVol1
ChAVol0
0
0
0
0
ChBVol3
ChBVol2
ChBVol1
ChBVol0
0
0
0
0
SubVol3
SubVol2
SubVol1
SubVol0
0
0
0
0
MuteADC
MuteSub
MuteChB
MuteChA
0
0
0
0
Min1
Min0
LimitAll
EnLimiter
0
0
1
0
RRate3
RRate2
RRate1
RRate0
1
1
1
1
ARate3
ARate2
ARate1
ARate0
0
0
0
0
PDnOut3/4 PDnOut2
PDnOut1
PDnAll
1
1
1
1
SRCLockM ADCOvflM
ChOvflM
AmpErrM
0
0
0
0
Ch1OvflSt RampDone Reserved
Reserved
x
x
0
0
ExtAmpSt
Reserved
UVTE1
UVTE0
x
0
x
x
DeviceID0
RevID2
RevID1
RevID0
1
x
x
x
DS726PP3
CS4525
9. REGISTER DESCRIPTIONS
All registers are read/write unless otherwise stated. All “Reserved” bits must maintain their default state.
9.1
Clock Configuration (Address 01h)
7
EnSysClk
9.1.1
6
DivSysClk
5
ClkFreq1
4
ClkFreq0
3
HP/MutePol
2
HP/Mute
1
PhaseShift
0
FreqShift
SYS_CLK Output Enable (EnSysClk)
Default = 1
Function:
This bit controls the output driver for the SYS_CLK signal. When cleared, the output driver is disabled and
the SYS_CLK pin is high-impedance. When set, the output driver is enabled.
If the SYS_CLK output is unused, this bit should be set to ‘0’b to disable the driver.
EnSysClk Setting
Output Driver State
0 ..........................................Output driver disabled.
1 ..........................................Output driver enabled.
9.1.2
SYS_CLK Output Divider (DivSysClk)
Default = 0
Function:
This bit determines the divider for the XTAL clock signal for generating the SYS_CLK signal.
This divider is only available if the clock source is an external crystal attached to XTI/XTO and the
SYS_CLK output is enabled.
DivSysClk Setting
SYS_CLK Output Frequency
0 ..........................................FSYS_CLK = FXTAL
1 ..........................................FSYS_CLK = FXTAL/2
9.1.3
Clock Frequency (ClkFreq[1:0])
Default = 01
Function:
These bits must be set to identify the nominal clock frequency of the crystal attached to the XTI/XTO pins
or that of the input SYS_CLK signal. See the XTI Switching Specifications table on page 23 and the
SYS_CLK Switching Specifications table on page 23 for complete input frequency range specifications.
ClkFreq[1:0] Setting
Specified Nominal Input Clock Frequency
00 ........................................18.432 MHz
01 ........................................24.576 MHz
10 ........................................27.000 MHz
11.........................................Reserved
DS726PP3
69
CS4525
9.1.4
HP_Detect/Mute Pin Active Logic Level (HP/MutePol)
Default = 0
Function:
This bit determines the active logic level for the HP_DETECT/MUTE input signal.
HP/MutePol Setting
Headphone Detect/Mute Input Polarity
0 .......................................... Active low.
1 .......................................... Active high.
9.1.5
HP_Detect/Mute Pin Mode (HP/Mute)
Default = 0
Function:
Configures the function of HP_DETECT/MUTE input pin. See “Headphone Detection & Hardware Mute
Input” on page 51 for more information.
HP/Mute Setting
HP_DETECT/MUTE Pin Function
0 .......................................... Mute input signal.
1 .......................................... Headphone detect input signal.
9.1.6
Modulator Phase Shifting (PhaseShift)
Default = 0
Function:
When enabled, forces the output of the PWM modulator to output differential signals which are the inverse
of each other and have been phase shifted by 180 degrees. This causes, for instance, the differential signal pair to be exactly in phase with one another during a mute condition, thereby reducing the amount of
switching current through the load.
PhaseShift Setting
Modulator Phase Shift State
0 .......................................... 180º phase shift disabled.
1 .......................................... 180º phase shift enabled.
9.1.7
AM Frequency Shifting (FreqShift)
Default = 0
Function:
Controls the state of the PWM AM frequency shift feature. See “PWM AM Frequency Shift” on page 51
for more information.
FreqShift Setting
AM Frequency Shift State
0 .......................................... Frequency shift disabled.
1 .......................................... Frequency shift enabled.
70
DS726PP3
CS4525
9.2
Input Configuration (Address 02h)
7
ADC/SP
9.2.1
6
EnAnHPF
5
Reserved
4
SPRate1
3
SPRate0
2
DIF2
1
DIF1
0
DIF0
Input Source Selection (ADC/SP)
Default = 0
Function:
This bit selects the audio input source.
ADC/SP Setting
Audio Input Source
0 ..........................................Digital input from the serial audio input port.
1 ..........................................Analog input from the internal ADC.
9.2.2
ADC High-Pass Filter Enable (EnAnHPF)
Default = 1
Function:
Controls the operation of the ADC high-pass filter.
EnAnHPF Setting
ADC High-Pass Filter State
0 ..........................................ADC high-pass filter disabled.
1 ..........................................ADC high-pass filter enabled.
9.2.3
Serial Port Sample Rate (SPRate[1:0]) - Read Only
Function:
Identifies the sample rate of the incoming LRCK signal on the serial audio input port based on the setting
of the ClkFreq[1:0] bits in Register 01h, the frequency of the internal system clock, and the frequency of
the input LRCK signal.
SPRate[1:0] Setting
Identified Input Sample Rate
00 ........................................32 kHz
01 ........................................44.1 kHz
10 ........................................48 kHz
11.........................................96 kHz
9.2.4
Input Serial Port Digital Interface Format (DIF [2:0])
Default = 000
Function:
Selects the serial audio interface format used for the data in on SDIN. The required relationship between
the Left/Right clock, serial clock and serial data is defined by the Digital Interface Format and the options
are detailed in the section “Serial Audio Interfaces” on page 62.
DIF[2:0] Setting
Input Serial Port Serial Audio Interface Format
000 ......................................Left-Justified, up to 24-bit data.
001 ......................................I²S, up to 24-bit data.
010 ......................................Right-Justified, 24-bit data.
011.......................................Right-Justified, 20-bit data.
100 ......................................Right-Justified, 18-bit data.
101 ......................................Right-Justified, 16-bit data.
110.......................................Reserved.
111 .......................................Reserved.
DS726PP3
71
CS4525
9.3
AUX Port Configuration (Address 03h)
7
EnAuxPort
9.3.1
6
DlyPortCfg1
5
DlyPortCfg0
4
AuxI²S/LJ
3
RChDSel1
2
RChDSel0
1
LChDSel1
0
LChDSel0
Enable Aux Serial Port (EnAuxPort)
Default = 0
Function:
Controls the operation of the auxiliary serial port.
EnAuxPort Setting
Auxiliary Port State
0 .......................................... Auxiliary port disabled.
1 .......................................... Auxiliary port enabled.
9.3.2
Delay & Warning Port Configuration (DlyPortCfg[1:0])
Default = 00
Function:
Controls the operation of the delay and warning port. See “Serial Audio Delay & Warning Input Port” on
page 44 for more information.
DlyPortCfg[1:0] Setting Delay Port Configuration
00 ........................................ Port disabled.
01 ........................................ Port configured as serial audio delay interface.
10 ........................................ Port configured as an external thermal warning indicator for the foldback algorithm.
11......................................... Port disabled.
9.3.3
Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ)
Default = 0
Function:
Selects the serial audio interface format for the data on AUX_SDOUT, DLY_SDIN, DLY_SDOUT. The required relationship between the Left/Right clock, serial clock and serial data is defined by the Digital Interface Format and the options are detailed in the “Serial Audio Interfaces” on page 62.
AuxI²S/LJ Setting
Auxiliary/Delay Port Serial Audio Interface Format
0 .......................................... Left-Justified, up to 24-bit.
1 .......................................... I²S, up to 24-bit.
9.3.4
Aux Serial Port Right Channel Data Select (RChDSel[1:0])
Default = 01
Function:
Selects the data to be sent over the right channel of the auxiliary port serial data output signal.
RChDSel[1:0] Setting
Aux Serial Port Right Channel Output Data Source
00 ........................................ Channel A.
01 ........................................ Channel B.
10 ........................................ Sub Channel.
11......................................... Channel B crossover high-pass output.
72
DS726PP3
CS4525
9.3.5
Aux Serial Port Left Channel Data Select (LChDSel[1:0])
Default = 00
Function:
Selects the data to be sent over the left channel of the auxiliary port serial data output signal.
LChDSel[1:0] Setting
Aux Serial Port Left Channel Output Data Source
00 ........................................Channel A.
01 ........................................Channel B.
10 ........................................Sub Channel.
11.........................................Channel B crossover low-pass output.
9.4
Output Configuration (Address 04h)
7
OutputCfg1
9.4.1
6
OutputCfg0
5
PWMDSel1
4
PWMDSel0
3
OutputDly3
2
OutputDly2
1
OutputDly1
0
OutputDly0
Output Configuration (OutputCfg[1:0])
Default = 00
Function:
Identifies the power output configuration. This parameter can only be changed when all modulators and
associated logic are in the power-down state (the PDnAll bit is set). Attempts to write this register while
the PDnAll is cleared will be ignored. See “Output Channel Configurations” on page 45 for more information.
OutputCfg[1:0] Setting
Power Output Configuration
00 ........................................Channel 1 & 2 Full-Bridge.
01 ........................................Channel 1 & 2 Half-Bridge + Sub Channel Full-Bridge.
10 ........................................Channel 1 Parallel Full-Bridge.
11.........................................Reserved.
9.4.2
PWM Signals Output Data Select (PWMDSel[1:0])
Default = 00
Function:
Selects the PWM data output on the PWM_SIG1 and PWM_SIG2 output signals.See “PWM_SIG LogicLevel Output Configurations” on page 49 for more information.
PWMDSel Setting
PWM Signal Output Mapping
00 ........................................PWM_SIG1 output disabled.
PWM_SIG2 output disabled.
01 ........................................Channel 1 output on PWM_SIG1.
Channel 2 output on PWM_SIG2.
10 ........................................Channel 1 output on PWM_SIG1.
Sub Channel output on PWM_SIG2.
11.........................................Channel 2 output on PWM_SIG1.
Sub Channel output on PWM_SIG2.
9.4.3
Channel Delay Settings (OutputDly[3:0])
Default = 0000
Function:
The channel delay bits allow delay adjustment of each of the power output audio channels. The value of
this register determines the amount of delay inserted in the output path. The delay time is calculated by
multiplying the register value by the period of the SYS_CLK or crystal input clock source. These bits can
DS726PP3
73
CS4525
only be changed while all modulators and associated logic are in the power-down state (the PDnAll bit is
set). Attempts to write these bits while the PDnAll bit is cleared will be ignored. See “PWM Channel Delay”
on page 55 for more information.
OutputDly[3:0] Setting
Output Delay in Input Clock Source Cycles
0000 .................................... 0 - No Delay
0001 .................................... 1
0010 .................................... 2
....................................
1000 .................................... 8
....................................
1111 ..................................... 15 - Max Delay
9.5
Foldback and Ramp Configuration (Address 05h)
7
SelectVP
9.5.1
6
EnTherm
5
LockAdj
4
AttackDly1
3
AttackDly0
2
EnFloor
1
RmpSpeed1
0
RmpSpeed0
Select VP Level (SelectVP)
Default = 1
Function:
Adjusts the PWM modulation index to maximize output power for applications with a nominal VP voltage
of less than or equal to 14 V. This bit must remain set for applications with a nominal VP voltage greater
than 14 V.
SelectVP Setting
Selected VP Level
0 .......................................... VP ≤ 14 Volts
1 .......................................... VP > 14 Volts.
9.5.2
Enable Thermal Foldback (EnTherm)
Default = 0
Function:
Enables the thermal foldback feature. See “Thermal Foldback” on page 40 for more information.
EnTherm Setting
Thermal Foldback State
0 .......................................... Disabled.
1 .......................................... Enabled.
9.5.3
Lock Foldback Adjust (LockAdj)
Default = 0
Function:
Controls the operation of the foldback lock adjustment feature. See “Thermal Foldback” on page 40 for
more information.
LockAdj Setting
Foldback Adjustment Lock State
0 .......................................... Attenuation lock disabled.
1 .......................................... Attenuation lock enabled.
74
DS726PP3
CS4525
9.5.4
Foldback Attack Delay (AttackDly[1:0])
Default = 01
Function:
Controls the foldback attack delay. See “Thermal Foldback” on page 40 for more information.
AttackDly[1:0] Setting
Foldback Attack Time
00 ........................................Approximately 0.5 seconds.
01 ........................................Approximately 1.0 seconds.
10 ........................................Approximately 1.5 seconds.
11.........................................Approximately 2.0 seconds.
9.5.5
Enable Foldback Floor (EnFloor)
Default = 0
Function:
Controls the foldback attenuation floor feature. See “Thermal Foldback” on page 40 for more information.
EnFloor Setting
Attenuation Floor
0 ..........................................No foldback attenuation floor imposed.
1 ..........................................Maximum foldback attenuation limited to -30 dB.
9.5.6
Ramp Speed (RmpSpd[1:0])
Default = 11
Function:
Controls the PWM output ramp speed. See “PWM Popguard Transient Control” on page 45 for more information.
RmpSpd[1:0] Setting
Ramp Speed
00 ........................................Fastest Ramp Speed
10 ........................................Slowest Ramp Speed
11.........................................Immediate. PWM Popguard Disabled.
9.6
Mixer / Pre-Scale Configuration (Address 06h)
7
PreScale2
9.6.1
6
PreScale1
5
PreScale0
4
Reserved
3
RChMix1
2
RChMix0
1
LChMix1
0
LChMix0
Pre-Scale Attenuation (PreScale[2:0])
Default = 000
Function:
Controls the pre-scale attenuation level. See “Pre-Scaler” on page 30 for more information.
PreScale[2:0] Setting
Pre-Scale Attenuation Setting
000 ......................................No pre-scale attenuation applied.
001 ......................................-2.0 dB
010 ......................................-4.0 dB
......................................
100 ......................................-8.0 dB
......................................
111 .......................................-14.0 dB
DS726PP3
75
CS4525
9.6.2
Right Channel Mixer (RChMix[1:0])
Default = 00
Function:
Controls the right channel mixer output. See “Channel Mixer” on page 30 for more information.
RChMix[1:0] Setting
Right Channel Mixer Output on Channel B
00 ........................................ Right Channel
01 ........................................ (Left Channel + Right Channel) / 2
10 ........................................ (Left Channel + Right Channel) / 2
11......................................... Left Channel
9.6.3
Left Channel Mixer (LChMix[1:0])
Default = 00
Function:
Controls the left channel mixer output. See “Channel Mixer” on page 30 for more information.
LChMix[1:0] Setting
Left Channel Mixer Output on Channel A
00 ........................................ Left Channel
01 ........................................ (Left Channel + Right Channel) / 2
10 ........................................ (Left Channel + Right Channel) / 2
11......................................... Right Channel
9.7
Tone Configuration (Address 07h)
7
DeEmph
9.7.1
6
Loudness
5
EnDigHPF
4
TrebFc1
3
TrebFc0
2
BassFc1
1
BassFc0
0
EnToneCtrl
De-Emphasis Control (DeEmph)
Default = 0
Function:
Controls the operation of the internal de-emphasis filter. See “De-Emphasis” on page 31 for more information.
DeEmph Setting
De-Emphasis State
0 .......................................... No de-emphasis applied.
1 .......................................... 44.1 kHz 50/15 µs de-emphasis filter applied.
9.7.2
Adaptive Loudness Compensation Control (Loudness)
Default = 0
Function:
Controls the operation of the adaptive loudness compensation feature. See “Adaptive Loudness Compensation” on page 34 for more information.
Loudness Setting
Adaptive Loudness Compensation State
0 .......................................... Disabled.
1 .......................................... Enabled.
76
DS726PP3
CS4525
9.7.3
Digital Signal Processing High-Pass Filter (EnDigHPF)
Default = 0
Function:
Controls the operation of the digital signal processing high-pass filter. See “Digital Signal Processing
High-Pass Filter” on page 30 for more information.
EnDigHPF Setting
Digital Signal Processing High-Pass Filter State
0 ..........................................Digital signal processing high-pass filter disabled.
1 ..........................................Digital signal processing high-pass filter enabled.
9.7.4
Treble Corner Frequency (TrebFc[1:0])
Default = 00
Function:
Sets the corner frequency for the treble shelving filter as shown below.
TrebFc[1:0] Setting
Treble Corner Frequency
00 ........................................Selects Treble Fc 0 - Approximately 5 kHz
01 ........................................Selects Treble Fc 1 - Approximately 7 kHz
10 ........................................Selects Treble Fc 2 - Approximately 10 kHz
11.........................................Selects Treble Fc 3 - Approximately 15 kHz
9.7.5
Bass Corner Frequency (BassFc[1:0])
Default = 01
Function:
Sets the corner frequency for the bass shelving filter as shown below.
BassFc[1:0] Setting
Bass Corner Frequency
00 ........................................Selects Bass Fc 0 - Approximately 50 Hz
01 ........................................Selects Bass Fc 1 - Approximately 100 Hz
10 ........................................Selects Bass Fc 2 - Approximately 200 Hz
11.........................................Selects Bass Fc 3 - Approximately 250 Hz
9.7.6
Tone Control Enable (EnToneCtrl)
Default = 0
Function:
When set, enables the bass and treble shelving filters. When cleared, disables the bass and treble shelving filters.
EnToneCtrl Setting
Tone Control Filter State
0 ..........................................Bass and treble shelving filters disabled.
1 ..........................................Bass and treble shelving filters enabled.
DS726PP3
77
CS4525
9.8
Tone Control (Address 08h)
7
Treble3
9.8.1
6
Treble2
5
Treble1
4
Treble0
3
Bass3
2
Bass2
1
Bass1
0
Bass0
Treble Gain Level (Treb[3:0])
Default = 1000
Function:
Sets the gain/attenuation level of the treble shelving filter.The level can be adjusted in 1.5 dB steps from
+12.0 to -10.5 dB.
Treb[3:0] Setting
Treble Shelving Filter Gain/Attenuation
0000 .................................... +12 dB
0001 .................................... +10.5 dB
.....................................
1000 .................................... 0 dB
.....................................
1110 ..................................... -9.0 dB
1111 ..................................... -10.5 dB
9.8.2
Bass Gain Level (Bass[3:0])
Default = 1000
Function:
Sets the gain/attenuation level of the bass shelving filter. The level can be adjusted in 1.5 dB steps from
+12.0 to -10.5 dB.
Bass[3:0] Setting
Bass Shelving Filter Gain/Attenuation
0000 .................................... +12 dB
0001 .................................... +10.5 dB
.....................................
1000 .................................... 0 dB
.....................................
1110 ..................................... -9.0 dB
1111 ..................................... -10.5 dB
9.9
2.1 Bass Manager/Parametric EQ Control (Address 09h)
7
Freeze
9.9.1
6
HiZPSig
5
BassMgr2
4
BassMgr1
3
BassMgr0
2
Reserved
1
EnChBPEq
0
EnChAPEq
Freeze Controls (Freeze)
Default = 0
Function:
This function will freeze the previous output of, and allow modifications to be made to the master volume
control (address 57h), channel X volume control (address 58h - 5Ah), and bi-quad coefficient registers for
channel A, and channel B (address 0Ah - 54h) without the changes taking effect until the Freeze bit is
disabled. To make multiple changes in these control port registers take effect simultaneously, enable the
Freeze bit, make all register changes, then disable the Freeze bit.
Freeze Setting
Register Freeze State
0 .......................................... Register freeze disabled.
1 .......................................... Register freeze enabled.
78
DS726PP3
CS4525
9.9.2
Hi-Z PWM_SIG Outputs (HiZPSig)
Default = 0
Function:
When cleared, the PWM_SIG1 and PWM_SIG2 output drivers are placed in a high-impedance state.
When set, the PWM_SIG1 and PWM_SIG2 output drivers are active. It should be noted that the function
of the PWM_SIG outputs is determined by the PWMDSel[1:0] bits in Register 04h.
HiZPSig Setting
PWM_SIG Output Driver State
0 ..........................................High impedance.
1 ..........................................Drivers active.
9.9.3
Bass Cross-Over Frequency (BassMgr[2:0])
Default = 000
Function:
Controls the operation and cross-over frequency of the bass manager. See “Bass Management” on
page 35 for more information.
BassMgr[2:0] Setting
Bass Manager Crossover Setting
000 ......................................Bass manager disabled.
001 ......................................Selects Bass Manager Frequency 1 - Approximately 80 Hz
010 ......................................Selects Bass Manager Frequency 2 - Approximately 120 Hz
011.......................................Selects Bass Manager Frequency 3 - Approximately 160 Hz
100 ......................................Selects Bass Manager Frequency 4 - Approximately 200 Hz
101 ......................................Selects Bass Manager Frequency 5 - Approximately 240 Hz
110.......................................Selects Bass Manager Frequency 6 - Approximately 280 Hz
111 .......................................Selects Bass Manager Frequency 7 - Approximately 320 Hz
9.9.4
Enable Channel B Parametric EQ (EnChBPEq)
Default = 0
Function:
Enables the parametric EQ bi-quad filters for channel B.
EnChBPEq Setting
Channel B Parametric EQ State
0 ..........................................Disabled.
1 ..........................................Enabled.
9.9.5
Enable Channel A Parametric EQ (EnChAPEq)
Default = 0
Function:
Enables the parametric EQ bi-quad filters for channel A.
EnChAPEq Setting
Channel A Parametric EQ State
0 ..........................................Disabled.
1 ..........................................Enabled.
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9.10
Volume and 2-Way Cross-Over Configuration (Address 55h)
7
SZCMode1
6
SZCMode0
5
Mute50/50
4
AutoMute
3
En2Way
2
2WayFreq2
1
2WayFreq1
0
2WayFreq0
9.10.1 Soft Ramp and Zero Cross Control (SZCMode[1:0])
Default = 10
Function:
Sets the soft ramp and zero crossing detection modes by which volume and muting changes will be implemented.
SZCMode[1:0] Setting
Soft Ramp & Zero Crossing Mode
00 ........................................ Immediate Change
When immediate change is selected, all level changes will take effect immediately in one step.
01 ........................................ Zero Cross
Zero cross dictates that signal level changes, both muting and attenuation, will occur on a signal
zero crossing to minimize audible artifacts. The requested level change will occur after a timeout
period (approximately 18.7 ms for a PWM switch rate of 384/768 kHz and 17.0 ms for a PWM
switch rate of 421.875/843.75 kHz) if the signal does not encounter a zero crossing. The zero cross
function is independently monitored and implemented for each channel.
10 ........................................ Soft Ramp
Soft ramp allows level changes, both muting and attenuation, to be implemented by incrementally
ramping, in ½ dB steps, from the current level to the new level at a rate of ½ dB per 4 sample periods for 32, 44.1, and 48 kHz, and ½ dB per 8 sample periods for 96 kHz.
11......................................... Soft Ramp on Zero Cross
Soft ramp on zero cross dictates that signal level changes, both muting and attenuation, will occur in
½ dB steps and be implemented on a signal zero crossing. The ½ dB level change will occur after a
timeout period (approximately 18.7 ms for a PWM switch rate of 384/768 kHz and 17.0 ms for a
PWM switch rate of 421.875/843.75 kHz) if the signal does not encounter a zero crossing. The zero
cross function is independently monitored and implemented for each channel.
9.10.2 Enable 50% Duty Cycle for Mute Condition (Mute50/50)
Default = 0
Function:
When set, the amplifiers will output a non-modulated 50%-duty-cycle signal for all mute conditions. This
bit does not cause a mute condition to occur. The Mute50/50 bit only defines operation during a normal
mute condition.
Mute50/50 Setting
50% Duty Cycle Mute State
0 .......................................... 50% duty cycle for mute conditions disabled.
1 .......................................... 50% duty cycle for mute conditions enabled.
9.10.3 Auto-Mute (AutoMute)
Default = 1
Function:
When enabled, the outputs of the CS4525 will mute following the reception of 8192 consecutive audio
samples of static 0 or -1. A single sample of non-static data will release the mute. Detection and muting
is done independently for each channel. See “Volume and Muting Control” on page 36 for more information.
AutoMute Setting
AutoMute State
0 .......................................... Auto-mute on static 0’s or -1’s disabled.
1 .......................................... Auto-mute on static 0’s or -1’s enabled.
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9.10.4 Enable 2-Way Crossover (En2Way)
Default = 0
Function:
Enables the 2-way crossover filters for channel 1 and channel 2.
En2Way Setting
2-Way Crossover State
0 ..........................................2-way crossover disabled.
1 ..........................................2-way crossover enabled.
9.10.5 2-Way Cross-Over Frequency (2WayFreq[2:0])
Default = 000
Function:
Selects the cross-over frequency for the 2-Way Linkwitz-Riley filters.
2WayFreq Setting
2-Way Crossover Frequency
000 ......................................Selects X-Over Freq 0 - Approximately 2.0 kHz
001 ......................................Selects X-Over Freq 1 - Approximately 2.2 kHz
010 ......................................Selects X-Over Freq 2 - Approximately 2.4 kHz
011.......................................Selects X-Over Freq 3 - Approximately 2.6 kHz
100 ......................................Selects X-Over Freq 4 - Approximately 2.8 kHz
101 ......................................Selects X-Over Freq 5 - Approximately 3.0 kHz
110.......................................Selects X-Over Freq 6 - Approximately 3.2 kHz
111 .......................................Selects X-Over Freq 7 - Approximately 3.4 kHz
9.11
Channel A & B: 2-Way Sensitivity Control (Address 56h)
7
LowPass3
9.11.1
6
LowPass2
5
LowPass1
4
LowPass0
3
HighPass3
2
HighPass2
1
HighPass1
0
HighPass0
Channel A and Channel B Low-Pass Sensitivity Adjust (LowPass[3:0])
Default = 0000
Function:
Controls the 2-way cross-over low-pass sensitivity adjustment. See “2-Way Crossover & Sensitivity Control” on page 42 for more information.
LowPass[3:0] Setting
Sensitivity Compensation Level
0000 ....................................0.0 dB
0001 ....................................-0.5 dB
0010 ....................................-1.0 dB
.....................................
1000 ....................................-4.0 dB
.....................................
1110 .....................................-7.0 dB
1111 .....................................-7.5 dB
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9.11.2
Channel A and Channel B High-Pass Sensitivity Adjust (HighPass[3:0])
Default = 0000
Function:
Controls the 2-way cross-over high-pass sensitivity adjustment. See “2-Way Crossover & Sensitivity Control” on page 42 for more information.
HighPass[3:0] Setting
Sensitivity Compensation Level
0000 .................................... 0.0 dB
0001 .................................... -0.5 dB
0010 .................................... -1.0 dB
.....................................
1000 .................................... -4.0 dB
.....................................
1110 ..................................... -7.0 dB
1111 ..................................... -7.5 dB
9.12
Master Volume Control (Address 57h)
7
MVol7
6
MVol6
5
MVol5
4
MVol4
3
MVol3
2
MVol2
1
MVol1
0
MVol0
9.12.1 Master Volume Control (MVol[7:0])
Default = 2Ah
Function:
Sets the gain/attenuation level of the master volume control. See “Volume and Muting Control” on
page 36 for more information.
MVol[7:0] Setting
Master Volume Setting
0000 0000 ........................... +24 dB
............................
0010 1010 ........................... +3 dB
............................
0011 0000............................ 0.0 dB
0011 0001............................ -0.5 dB
0011 0010............................ -1.0 dB
............................
1111 1110............................. -103.0 dB
1111 1111 ............................. Master Mute
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9.13
Channel A and B Volume Control (Address 58h & 59h)
7
ChXVol7
6
ChXVol6
5
ChXVol5
4
ChXVol4
3
ChXVol3
2
ChXVol2
1
ChXVol1
0
ChXVol0
9.13.1 Channel X Volume Control (ChXVol[7:0])
Default = 30h
Function:
Sets the gain/attenuation levels of channel A and channel B. See “Volume and Muting Control” on
page 36 for more information.
ChXVol[7:0] Setting
Channel X Volume Setting
0000 0000 ...........................+24 dB
............................
0011 0000............................0.0 dB
0011 0001............................-0.5 dB
0011 0010............................-1.0 dB
............................
1111 1110.............................-103.0 dB
1111 1111 .............................Channel Mute
9.14
Sub Channel Volume Control (Address 5Ah)
7
SubVol7
6
SubVol6
5
SubVol5
4
SubVol4
3
SubVol3
2
SubVol2
1
SubVol1
0
SubVol0
9.14.1 Sub Channel Volume Control (SubVol[7:0])
Default = 30h
Function:
Sets the gain/attenuation levels of the sub channel. See “Volume and Muting Control” on page 36 for more
information.
SubVol[7:0] Setting
Sub Channel Volume Setting
0000 0000 ...........................+24 dB
............................
0011 0000............................0.0 dB
0011 0001............................-0.5 dB
0011 0010............................-1.0 dB
............................
1111 1110.............................-103.0 dB
1111 1111 .............................Channel Mute
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9.15
Mute/Invert Control (Address 5Bh)
7
InvADC
6
InvSub
5
InvCh2
4
InvCh1
3
MuteADC
2
MuteSub
1
MuteChB
0
MuteChA
9.15.1 ADC Invert Signal Polarity (InvADC)
Default = 0
Function:
When set, the signal polarity of the ADC will be inverted.
InvADC Setting
ADC Signal Inversion State
0 .......................................... ADC signal polarity not inverted.
1 .......................................... ADC signal polarity inverted.
9.15.2 Invert Channel PWM Signal Polarity (InvChX)
Default = 0
Function:
When set, the respective channel’s power and logic-level PWM output signal polarity will be inverted. The
serial output on the auxiliary and delay ports are unaffected.
InvChX Setting
Channel X PWM Signal Inversion State
0 .......................................... Channel X PWM signal polarity not inverted.
1 .......................................... Channel X PWM signal polarity inverted.
9.15.3 Invert Sub PWM Signal Polarity (InvSub)
Default = 0
Function:
When set, the Sub channel’s power and logic-level PWM output polarity will be inverted. The serial output
on the auxiliary port is unaffected.
InvSub Setting
Sub Channel PWM Signal Inversion State
0 .......................................... Sub channel PWM signal polarity not inverted.
1 .......................................... Sub channel PWM signal polarity inverted.
9.15.4 ADC Channel Mute (MuteADC)
Default = 0
Function:
The output of the ADC will mute when enabled.
MuteADC Setting
ADC Mute State
0 .......................................... ADC un-muted.
1 .......................................... ADC muted.
9.15.5 Independent Channel A & B Mute (MuteChX)
Default = 0
Function:
The respective channel’s power PWM, logic-level PWM, and auxiliary serial data outputs will enter a mute
state when enabled. The delay serial output will be unaffected if the delay port is enabled. The muting
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function is affected, similar to attenuation changes, by the soft and zero cross bits (SZCMode[1:0]). See
“Volume and Muting Control” on page 36 for more information.
MuteChX Setting
Channel X PWM Mute State
0 ..........................................Channel X PWM outputs un-muted.
1 ..........................................Channel X PWM outputs muted.
9.15.6 Sub Channel Mute (MuteSub)
Default = 0
Function:
The sub channel’s power PWM, logic-level PWM, and auxiliary serial data outputs will enter a mute state
when enabled. The muting function is affected, similar to attenuation changes, by the soft and zero cross
bits (SZCMode[1:0]). See “Volume and Muting Control” on page 36 for more information.
MuteSub Setting
Sub Channel PWM Mute State
0 ..........................................Sub channel PWM outputs un-muted.
1 ..........................................Sub channel PWM outputs muted.
9.16
Limiter Configuration 1 (Address 5Ch)
7
Max2
6
Max1
5
Max0
4
Min2
3
Min1
2
Min0
1
LimitAll
0
EnLimiter
9.16.1 Maximum Threshold (Max[2:0])
Default = 000
Function:
Sets the maximum level, below full scale, at which to limit and attenuate the output signal at the limiter
attack rate.
Max[2:0] Setting
Maximum Threshold Setting
000 ......................................0.0 dB
001 ......................................-3.0 dB
010 ......................................-6.0 dB
011.......................................-9.0 dB
100 ......................................-12.0 dB
101 ......................................-18.0 dB
110.......................................-24.0 dB
111 .......................................-30.0 dB
9.16.2 Minimum Threshold (Min[2:0])
Default = 000
Function:
Sets a minimum level below full scale at which the limiter will begin to release its applied attenuation.
Min[2:0] Setting
Minimum Threshold Setting
000 ......................................0.0 dB
001 ......................................-3.0 dB
010 ......................................-6.0 dB
011.......................................-9.0 dB
100 ......................................-12.0 dB
101 ......................................-18.0 dB
110.......................................-24.0 dB
111 .......................................-30.0 dB
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9.16.3 Peak Signal Limit All Channels (LimitAll)
Default = 1
Function:
When cleared, the peak signal limiter will limit the maximum signal amplitude to prevent clipping on the
specific channel indicating clipping. The other channels will not be affected. When set, the peak signal
limiter will limit the maximum signal amplitude to prevent clipping on all channels in response to any single
channel indicating clipping. See “Peak Signal Limiter” on page 37 for more information.
LimitAll Setting
Limit All Channels Configuration
0 .......................................... Only individual channels affected by any limiter event.
1 .......................................... All channels affected by any limiter event.
9.16.4 Peak Detect and Limiter Enable (EnLimiter)
Default = 0
Function:
Limits the maximum signal amplitude to prevent clipping when this function is enabled. Peak signal limiting is performed by digital attenuation.
EnLimiter Setting
Peak Signal Limiter State
0 .......................................... Peak signal limiter disabled.
1 .......................................... Peak signal limiter enabled.
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9.17
Limiter Configuration 2 (Address 5Dh)
7
Reserved
6
Reserved
5
RRate5
4
RRate4
3
RRate3
2
RRate2
1
RRate1
0
RRate0
9.17.1 Limiter Release Rate (RRate[5:0])
Default = 111111
Function:
Sets the rate at which the limiter releases the digital attenuation from levels below the minimum setting in
the limiter threshold register.
The limiter release rate is a function of the sampling frequency, Fs, and the soft and zero cross setting.
RRate[5:0] Setting
Limiter Release Rate
000000 ................................Fastest release.
...................................
111111..................................Slowest release.
9.18
Limiter Configuration 3 (Address 5Eh)
7
EnThLim
6
Reserved
5
ARate5
4
ARate4
3
ARate3
2
ARate2
1
ARate1
0
ARate0
9.18.1 Enable Thermal Limiter (EnThLim)
Default = 0
Function:
When set, enables the thermal limiter function. The thermal limiter function adds an additional -3dB of attenuation to the min and max settings of the peak signal limiter the first time a thermal warning is detected
after the thermal limiter function has been enabled. For more details, see the “Thermal Limiter” section on
page 39.
EnThLim Setting
Thermal Limiter State
0 ..........................................Thermal limiter disabled.
1 ..........................................Thermal limiter enabled.
9.18.2 Limiter Attack Rate (ARate[5:0])
Default = 000000
Function:
Sets the rate at which the limiter attenuates the analog output from levels above the maximum setting in
the limiter threshold register. The limiter attack rate is a function of the sampling frequency, Fs, and the
soft and zero cross setting.
ARate[5:0] Setting
Limiter Attack Rate
00000 ..................................Fastest attack.
...................................
11111....................................Slowest attack.
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9.19
Power Control (Address 5Fh)
7
AutoRetry
6
EnOCProt
5
SelectVD
4
PDnADC
3
PDnOut3/4
2
PDnOut2
1
PDnOut1
0
PDnAll
9.19.1 Automatic Power Stage Retry (AutoRetry)
Default = 1
Function:
Enables the Auto-Retry function upon over-current error. See “Automatic Power Stage Shut-Down” on
page 53.
AutoRetry Setting
Auto-Retry State
0 .......................................... Auto-Retry feature disabled.
1 .......................................... Auto-Retry feature enabled.
9.19.2 Enable Over-Current Protection (EnOCProt)
Default = 1
Function:
Enables the PWM power output over-current protection feature described in “Automatic Power Stage
Shut-Down” on page 53.
WARNING: The EnOCProt bit must never to changed from its default value of 1. Doing so will disable the over-current protection feature and may result in permanent damage to the CS4525.
9.19.3 Select VD Level (SelectVD)
Default = 1
Function:
This bit selects between a VD of 2.5 V, 3.3 V, or 5.0 V.
SelectVD Setting
Selected VD Level
0 .......................................... VD = 2.5 V.
1 .......................................... VD = 3.3 V or 5.0 V.
9.19.4 Power Down ADC (PDnADC)
Default = 1
Function:
The ADC will enter a power down state when this bit is enabled.
PDnADC Setting
ADC Power-Down State
0 .......................................... Normal ADC operation.
1 .......................................... ADC power-down enabled.
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9.19.5 Power Down PWM Power Output X (PDnOutX)
Default = 1
Function:
When set, the specific PWM power output will enter a power-down state. Only the output power stage is
powered down. The PWM modulator is not affected, nor is the setup or delay register values. When set
to normal operation, the specific output will power up according to the state of the RmpSpd[1:0] bits and
the channel output configuration selected. When transitioning from normal operation to power down, the
specific output will power down according to the state of the RmpSpd[1:0] bits and the channel output configuration selected.
PDnChX Setting
Power Output X Power-Down State
0 ..........................................Normal power output X operation.
1 ..........................................Power output X power-down enabled.
The entire divide will enter a low-power state when this function is enabled:
9.19.6 Power Down (PDnAll)
Default = 1
Function:
The CS4525 will enter a power-down state when this function is enabled:
1. The power PWM outputs will be held in a high-impedance state.
2. The logic-level PWM outputs will continuously drive a logic ‘0’ if the HiZPSig bit is set and will be held
in a high-impedance state if the HiZPSig bit is clear.
3. AUX_SDOUT, the auxiliary serial data output, will be driven to a digital-low. AUX_LRCK and
AUX_SCLK, the auxiliary serial output’s clocks, will continue to operate if the EnAuxPort bit is set,
ADC/SP is cleared, and the serial audio input receives a valid SCLK and LRCK; otherwise they will
also be driven to a digital-low voltage.
4. DLY_SDOUT, the delay serial data output, will output the unprocessed audio data from SDATA if
EnAuxPort is set, DlyPortCfg[1:0] is configured for serial output delay interface, ADC/SP is cleared,
and the serial audio input port receives a valid SCLK, LRCK, and SDATA. Otherwise, it will drive a
low voltage.
The contents of the control registers are retained in this state. Once the PDnAll bit is disabled, the powered and logic-level PWM outputs will first perform a click-free start-up function and then resume normal
operation.
The PDnAll bit defaults to ‘enabled’ on power-up and must be disabled before normal operation can occur.
PDnAll Setting
Device Power-Down State
0 ..........................................Normal device operation.
1 ..........................................Device power-down enabled.
9.20
Interrupt (Address 60h)
7
SRCLock
6
ADCOvfl
5
ChOvfl
4
AmpErr
3
SRCStateM
2
ADCOvflM
1
ChOvflM
0
AmpErrM
Bits [7:4] in this register are read only. A ‘1’b in these bit positions indicates that the associated condition has occurred at least once since the register was last read. A ‘0’b indicates that the associated condition has not occurred
since the last reading of the register. Reading the register resets bits to [7:4] ‘0’b. These bits are considered “edgetriggered” events. The operation of these 4 bits is not affected by the interrupt mask bits and the condition of each
bit can be polled instead of generating an interrupt as required.
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9.20.1 SRC Lock State Transition Interrupt (SRCLock)
Function:
This bit is read only. When set, indicates that the SRC has transitioned from an unlock to lock state or
from a lock state to an unlock state since the last read of this register. Conditions which cause the SRC
to transition states, such as loss of LRCK, SCLK, an LRCK ratio change, or the SRC achieving lock, will
cause this bit to be set. This interrupt bit is an edge-triggered event and will be cleared following a read
of this register.
If this bit is set, indicating a SRC state change condition, and the SRCLockM bit is set, the INT pin will go
active. To determine the current lock state of the SRC, read the SRCLockSt bit in the interrupt status register.
SRCLock Setting
SRC Lock State Change Status
0 .......................................... SRC lock state unchanged since last read of this register.
1 .......................................... SRC lock state changed since last read of this register.
9.20.2 ADC Overflow Interrupt (ADCOvfl)
Function:
This bit is read only. When set, indicates that an over-range condition occurred anywhere in the CS4525
ADC signal path and has been clipped to positive or negative full scale as appropriate since the last read
of this register. This interrupt bit is an edge-triggered event and will be cleared following a read of this
register.
If this bit is set, indicating an ADC over-range condition, and the ADCOvflM bit is set, the INT pin will go
active. To determine the current overflow state of the ADC, read the ADCOvflSt bit in the interrupt status
register.
ADCOvfl Setting
ADC Overflow Event Status
0 .......................................... ADC overflow condition has not occurred since last read of this register.
1 .......................................... ADC overflow condition has occurred since last read of this register.
9.20.3 Channel Overflow Interrupt (ChOvfl)
Function:
This bit is read only. When set, indicates that the magnitude of an output sample on channel 1, 2, or the
Sub channel has exceeded full scale and has been clipped to positive or negative full scale as appropriate
since the last read of this register. This interrupt bit is an edge-triggered event and will be cleared following
a read of this register.
If this bit is set, indicating a channel over-range condition, and the ChOvflM bit is set, the INT pin will go
active. To determine the current overflow state of each channel, read the ChXOvflSt and SubOvflSt bits
in the interrupt status register.
ChOvfl Setting
Channel Overflow Event Status
0 .......................................... A channel overflow condition has not occurred since last read of this register.
1 .......................................... A channel overflow condition has occurred since last read of this register.
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9.20.4 Amplifier Error Interrupt Bit (AmpErr)
Function:
This bit is read only. When set, indicates that an error was detected in the power amplifier section since
the last read of this register. This interrupt bit is an edge-triggered event and will be cleared following a
read of this register. This bit is the logical OR of all the bits in the amplifier error status register. Read the
amplifier error status register to determine which condition occurred.
If this bit is set, indicating an amplifier stage error condition, and the AmpErrM bit is set to a ‘1’b, the INT
pin will go active. To determine the actual current state of the amplifier error condition, read the amplifier
error status register.
AmpErr Setting
Amplifier Error Event Status
0 ..........................................An amplifier error condition has not occurred since last read of this register.
1 ..........................................An amplifier error condition has occurred since last read of this register.
9.20.5 Mask for SRC State (SRCLockM)
Default = 0
Function:
This bit serves as a mask for the SRC status interrupt source. If this bit is set, the SRCLock interrupt is
unmasked, meaning that if the SRCLock bit is set, the INT pin will go active. If the SRCLockM bit is
cleared, the SRCLock condition is masked, meaning that its occurrence will not affect the INT pin. However, the SRCLock and SRCLockSt bits will continue to reflect the lock status of the SRC.
SRCLockM Setting
SRCLock INT Pin Mask State
0 ..........................................SRCLock condition masked.
1 ..........................................SRCLock condition un-masked.
9.20.6 Mask for ADC Overflow (ADCOvflM)
Default = 0
Function:
This bit serves as a mask for the ADC overflow interrupt source. If this bit is set, the ADCOvfl interrupt is
unmasked, meaning that if the ADCOvfl bit is set, the INT pin will go active. If the ADCOvflM bit is cleared,
the ADCOvfl condition is masked, meaning that its occurrence will not affect the INT pin. However, the
ADCOvfl and ADCOvflSt bits will continue to reflect the overflow state of the ADC.
ADCOvflM Setting
ADCOvfl INT Pin Mask State
0 ..........................................ADCOvfl condition masked.
1 ..........................................ADCOvfl condition un-masked.
9.20.7 Mask for Channel X and Sub Overflow (ChOvflM)
Default = 0
Function:
This bit serves as a mask for the channel 1, 2, and Sub overflow interrupt source. If this bit is set, the ChOvfl interrupt is unmasked, meaning that if the ChOvfl bit is set, the INT pin will go active. If the ChOvflM bit
is cleared, the ChOvfl condition is masked, meaning that its occurrence will not affect the INT pin. However, the ChOvfl, ChXOvflSt, and SubOvflSt bits will continue to reflect the overflow state of the individual
channels.
ChOvflM Setting
ChOvfl INT Pin Mask State
0 ..........................................ChOvfl condition masked.
1 ..........................................ChOvfl condition un-masked.
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9.20.8 Mask for Amplifier Error (AmpErrM)
Default = 0
Function:
This bit serves as a mask for the amplifier error interrupt sources. If this bit is set, the AmpErr interrupt is
unmasked, meaning that if the AmpErr bit is set, the INT pin will go active. If the AmpErrM bit is cleared,
the AmpErr condition is masked, meaning that its occurrence will not affect the INT pin. However, the AmpErr and the amplifier error bits in the amplifier error status register will continue to reflect the status of the
amplifier error conditions.
AmpErrM Setting
AmpErr INT Pin Mask State
0 .......................................... AmpErr condition masked.
1 .......................................... AmpErr condition un-masked.
9.21
Interrupt Status (Address 61h) - Read Only
7
SRCLockSt
6
ADCOvflSt
5
SubOvflSt
4
Ch2OvflSt
3
Ch1OvflSt
2
RampDone
1
Reserved
0
Reserved
All bits in this register are considered “level-triggered” events, meaning as long as a condition continues, the corresponding bit will remain set. These status bits are not affected by the interrupt mask bit and the condition of each bit
can be polled. These bits will not be cleared following a read to this register, nor can they be written to cause an
interrupt condition.
9.21.1 SRC State Transition (SRCLockSt)
Function:
This bit is read only and reflects the current lock state of the SRC. When set, indicates the SRC is currently
locked. When cleared, indicates the SRC is currently unlocked.
SRCLockSt Setting
SRC Lock State
0 .......................................... SRC is currently unlocked.
1 .......................................... SRC is currently locked.
9.21.2 ADC Overflow (ADCOvflSt)
Function:
This bit is read only and will identify the presence of an overflow condition within the ADC. When set, indicates that an over-range condition is currently occurring in the CS4525 ADC signal path and has been
clipped to positive or negative full scale.
ADCOvflSt Setting
ADC Overflow State
0 .......................................... An ADC overflow condition is not currently present.
1 .......................................... An ADC overflow condition is currently present.
9.21.3 Sub Overflow (SubOvflSt)
Function:
This bit is read only and will identify the presence of an overflow condition anywhere in the Sub channel’s
signal path. When set, indicates that an over-range condition is currently occurring in the Sub channel’s
signal path and has been clipped to positive or negative full scale.
SubOvflSt Setting
Sub Overflow State
0 .......................................... An overflow condition is not currently present on the Sub channel.
1 .......................................... An overflow condition is currently present on the Sub channel.
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9.21.4 Channel X Overflow (ChXOvflSt)
Function:
These bits are read only and will identify the presence of an overflow condition anywhere in the associated
channel’s signal path. When set, indicates that an over-range condition is currently occurring in the channel’s signal path and has been clipped to positive or negative full scale.
ChXOvflSt Setting
Channel X Overflow State
0 ..........................................An overflow condition is not currently present on channel X.
1 ..........................................An overflow condition is currently present on channel X.
9.21.5 Ramp-Up Cycle Complete (RampDone)
Function:
When set, indicates that all active channels have completed the configured ramp-up interval.
RampDone Setting
Ramp Completion State
0 ..........................................Ramp-up interval not completed on all channels.
1 ..........................................Ramp-up interval completed on all channels.
9.22
Amplifier Error Status (Address 62h) - Read Only
7
OverCurr4
6
OverCurr3
5
OverCurr2
4
OverCurr1
3
ExtAmpErr
2
Reserved
1
UVTE1
0
UVTE0
All bits in this register are considered “level-triggered” events, meaning as long as a condition continues, the corresponding bit will remain set. These status bits are not affected by the interrupt mask bit and the condition of each bit
can be polled. These bits will not be cleared following a read to this register, nor can they be written to cause an
interrupt condition.
9.22.1 Over-Current Detected On Channel X (OverCurrX)
Function:
When set, indicates an over current condition is currently present on the corresponding amplifier output.
OverCurrX Setting
Amplifier Over-Current Status
0 ..........................................An over current condition is not currently present on amplifier output X.
1 ..........................................An over current condition is currently present on amplifier output X.
9.22.2 External Amplifier State (ExtAmpSt)
Function:
When set, indicates a thermal warning condition is currently being reported by an external amplifier. For
proper operation, the delay serial port must be configured to support an external thermal warning input
signal. This status bit reflects the active state of the external thermal warning input signal.
ExtAmpSt Setting
External Amplifier Status
0 ..........................................A thermal warning condition is not currently being reported by an external amplifier.
1 ..........................................A thermal warning condition is currently being reported by an external amplifier.
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CS4525
9.22.3 Under Voltage / Thermal Error State (UVTE[1:0])
Function:
Indicates the operational status of the amplifier. These bits can identify a Thermal Warning condition, a
Thermal Error condition, or an Under Voltage condition. The thresholds for each of these conditions is
listed in the PWM Power Output Characteristics table on page 20.
UVTE[1:0] Setting
Under Voltage & Thermal Error Status
00 ........................................ The device is operating normally.
01 ........................................ The device is operating normally; however a Thermal Warning condition is being reported.
10 ........................................ An Under Voltage condition is currently present.
11......................................... A Thermal Error condition is currently present.
9.23
Device I.D. and Revision (Address 63h) - Read Only
7
DeviceID4
6
DeviceID3
5
DeviceID2
4
DeviceID1
3
DeviceID0
2
RevID2
1
RevID1
0
RevID0
9.23.1 Device Identification (DeviceID[4:0])
Default =11111
Function:
Identification code for the CS4525.
DeviceID[4:0] Setting
Device ID Notes
11111.................................... Permanent device identification code.
9.23.2 Device Revision (RevID[2:0])
Function:
Identifies the CS4525 device revision.
RevID[2:0] Setting
Device Revision
000 ...................................... Revision A0 and B0.
010 ...................................... Revision C0.
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10.PARAMETER DEFINITIONS
Dynamic Range (DYR)
The ratio of the rms value of the signal to the rms sum of all other spectral components over the specified
bandwidth, typically 20 Hz to 20 kHz. Dynamic Range is a signal-to-noise ratio measurement over the specified band width made with a -60 dBFS signal. 60 dB is then added to the resulting measurement to refer
the measurement to full-scale. This technique ensures that the distortion components are below the noise
level and do not effect the measurement. This measurement technique has been accepted by the Audio
Engineering Society, AES17-1991, and the Electronic Industries Association of Japan, EIAJ CP-307. Expressed in decibels.
Total Harmonic Distortion + Noise (THD+N)
The ratio of the rms value of the signal to the rms sum of all other spectral components over the specified
band width (typically 10 Hz to 20 kHz), including distortion components. Expressed in decibels. Measured
as suggested in AES17-1991 Annex A.
Frequency Response
FR is the deviation in signal level verses frequency. The 0 dB reference point is 1 kHz. The amplitude corner, Ac, lists the maximum deviation in amplitude above and below the 1 kHz reference point. The listed
minimum and maximum frequencies are guaranteed to be within the Ac from minimum frequency to maximum frequency inclusive.
Interchannel Isolation
A measure of crosstalk between the left and right channels. Measured for each channel at the converter's
output with no signal to the input under test and a full-scale signal applied to the other channel. Units in decibels.
Interchannel Gain Mismatch
The gain difference between left and right channels. Units in decibels.
Gain Drift
The change in gain value with temperature. Units in ppm/°C.
Fs
Sampling Frequency.
Resolution
The number of bits in a serial audio data word.
SRC
Sample Rate Converter. Converts data derived at one sample rate to a differing sample rate.
11.REFERENCES
1. Cirrus Logic, “AN18: Layout and Design Rules for Data Converters and Other Mixed Signal Devices,”
Version 6.0, February 1998.
2. Cirrus Logic, “AN22: Overview of Digital Audio Interface Data Structures, Version 2.0”, February 1998.; A
useful tutorial on digital audio specifications.
3. Philips Semiconductor, “The I²C-Bus Specification: Version 2,” Dec. 1998.
http://www.semiconductors.philips.com
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CS4525
12.PACKAGE DIMENSIONS
48L QFN (9 × 9 MM BODY) PACKAGE DRAWING
e
b
D
Pin #1 ID
Pin #1 ID
E
E2
A1
L
D2
A
Top View
DIM
MIN
A
A1
b
D
D2
E
E2
e
L
-0.0000
0.0118
0.2618
0.2618
0.0177
Side View
INCHES
NOM
--0.0138
0.3543 BSC
0.2677
0.3543 BSC
0.2677
0.0256 BSC
0.0217
Bottom View
MAX
MIN
0.0354
0.0020
0.0157
-0.00
0.30
0.2736
6.65
0.2736
6.65
0.0276
0.45
MILLIMETERS
NOM
--0.35
9.00 BSC
6.80
9.00 BSC
6.80
0.65 BSC
0.55
NOTE
MAX
0.90
0.05
0.40
1
1
1,2
1
1
1
1
1
1
6.95
6.95
0.70
JEDEC #: MO-220
Controlling Dimension is Millimeters.
Table 22:
Notes:
1. Dimensioning and tolerance per ASME Y4.5M - 1994.
2. Dimensioning lead width applies to the plated terminal and is measured between 0.20 mm and
0.25 mm from the terminal tip.
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13.THERMAL CHARACTERISTICS
Parameter
Symbol
Min
Typ
Max
Units
θJC
-
1
-
°C/Watt
Junction to Case Thermal Impedance
13.1
Thermal Flag
This device is designed to have the metal flag on the bottom of the device soldered directly to a metal plane
on the PCB. To enhance the thermal dissipation capabilities of the system, this metal plane should be coupled with vias to a large metal plane on the backside (and inner ground layer, if applicable) of the PCB.
In either case, it is beneficial to use copper fill in any unused regions inside the PCB layout, especially those
immediately surrounding the CS4525. In addition to improving in electrical performance, this practice also
aids in heat dissipation.
The heat dissipation capability required of the metal plane for a given output power can be calculated as
follows:
θCA = [(TJ(MAX) - TA) / PD] - θJC
where,
θCA = Thermal resistance of the metal plane in °C/Watt
TJ(MAX) = Maximum rated operating junction temperature in °C, equal to 150 °C
TA = Ambient temperature in °C
PD = RMS power dissipation of the device, equal to 0.176*PRMS-OUT (assuming 85% efficiency)
θJC = Junction-to-case thermal resistance of the device in °C/Watt
14.ORDERING INFORMATION
Product
Description
Digital Audio Amp
with Integrated ADC
Rail
CS4525-CNZ
CS4525
48-QFN
Yes
Commercial
0° to +70°C
Tape and
Reel
CS4525-CNZR
CRD4525-Q1
4 Layer / 1oz. Copper
Reference Design
Board
-
-
-
-
-
CRD4525-Q1
CRD4525-D1
2 Layer / 1oz. Copper
Reference Design
Board
-
-
-
-
-
CRD4525-D1
DS726PP3
Package Pb-Free
Grade
Temp Range Container
Order#
97
CS4525
15.REVISION HISTORY
Release
Changes
PP1
The following items were updated:
“Analog Input Characteristics” on page 19
“PWM Power Output Characteristics” on page 20
“XTI Switching Specifications” on page 23
“SYS_CLK Switching Specifications” on page 23
“Digital Interface Specifications” on page 25
Section 6.4.1 “Half-Bridge Output Filter” on page 59
Section 6.4.2 “Full-Bridge Output Filter (Stereo or Parallel)” on page 60
Table 21, “Power Supply Configuration and Settings,” on page 63
Section 9.19.3 “Select VD Level (SelectVD)” on page 88
PP2
Added Section 9.19.2 “Enable Over-Current Protection (EnOCProt)” on page 88
PP3
Updated the temperature range shown in the General Description on page 2, in the Recommended Operating Conditions table on page 18, and in the Ordering Information table on page 97.
Updated the description of the CLK_FREQ1 pin in Section 2. “Pin Descriptions - Hardware Mode” on
page 10.
Added reference to Note 16 to the Output Sample Rate and AUX_SCLK Frequency specifications in the
AUX Serial Audio I/O Port Switching Specifications table on page 22.
Updated Note 15 on page 23.
Added Note 16 on page 23.
Updated the Software Mode Power-Up and Power-Down sequences in sections 6.1.2.1 and 6.1.2.2.
Updated Section 6.2.1 “System Clocking” on page 54 to reflect the requirement for the CLK_FREQ1 pin to
be connected to DGND.
Updated the Hardware Mode Power-Up and Power-Down sequences in sections 6.2.2.1 and 6.2.2.2.
Updated Section 6.4.1 “Half-Bridge Output Filter” on page 59
Updated Section 6.4.2 “Full-Bridge Output Filter (Stereo or Parallel)” on page 60
Added Section 7.2 “Output Filter Layout” on page 65
Re-defined PD in terms of PRMS-OUT in the “Thermal Flag” section on page 97.
Contacting Cirrus Logic Support
For all product questions and inquiries, contact a Cirrus Logic Sales Representative.
To find one nearest you, go to www.cirrus.com.
IMPORTANT NOTICE
“Preliminary” product information describes products that are in production, but for which full characterization data is not yet available. Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and
is provided “AS IS” without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant information to verify, before
placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order
acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third parties. This document
is the property of Cirrus and by furnishing this information, Cirrus grants no license, express or implied under any patents, mask work rights, copyrights, trademarks,
trade secrets or other intellectual property rights. Cirrus owns the copyrights associated with the information contained herein and gives consent for copies to be
made of the information only for use within your organization with respect to Cirrus integrated circuits or other products of Cirrus. This consent does not extend to
other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED FOR USE
IN PRODUCTS SURGICALLY IMPLANTED INTO THE BODY, AUTOMOTIVE SAFETY OR SECURITY DEVICES, LIFE SUPPORT PRODUCTS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF CIRRUS PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK AND CIRRUS DISCLAIMS AND MAKES NO WARRANTY, EXPRESS, STATUTORY OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR PARTICULAR PURPOSE, WITH REGARD TO ANY CIRRUS PRODUCT THAT IS USED IN SUCH A MANNER. IF THE CUSTOMER OR CUSTOMER’S CUSTOMER USES OR PERMITS THE USE OF CIRRUS PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY SUCH USE, TO FULLY
INDEMNIFY CIRRUS, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL LIABILITY, INCLUDING ATTORNEYS’ FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES.
Cirrus Logic, Cirrus, and the Cirrus Logic logo designs, and Popguard are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may
be trademarks or service marks of their respective owners.
I²C is a registered trademark of Philips Semiconductor.
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