Cirrus CS4525 30 w digital tv amplifier with integrated adc Datasheet

CS4525
30 W Digital TV 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
–
–
Programmable Power Foldback on
Thermal Warning
High Efficiency (85%)
! 95 dB Dynamic Range (A-wtd)
! -88 dB THD+N
! 2 Vrms Input Supports SCART
! > 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
! PWM Popguard® for Half-Bridge Mode
! Spread Spectrum PWM Modulation
! Click Free Start-Up
–
! Programmable Channel Delay for System
Reduces EMI Radiated Energy
! Low Quiescent Current
Noise & Radiated Emissions Management
(Features continued on page 2)
2.5 V to 5 V
10.5 V to 18 V
VP
System Clock
Crystal Driver
I/O
Audio
Processing
Gate
Drive
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
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
Register /Hardware
Configuration
I²C or Hardware
Configuration
Advance Product Information
http://www.cirrus.com
PWM Modulator
Output 1
Error Protection
Thermal Warning
Over Current
Thermal Feedback
Under Voltage
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. 2006
(All Rights Reserved)
AUGUST '06
DS726A1
CS4525
Software Mode System Features
Common Applications
! Digital Audio Processing
! Integrated Digital TV’s
–
–
–
–
–
–
–
–
–
3 Programmable Parametric EQ Filters for
Channels 1 and 2
2 Programmable Parametric EQ Filters for
Channel 3
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 for 32 kHz, 44.1 kHz, 48 kHz
! 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
! 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
! 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 and 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, 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 (-10° to +70° C). The CRD4525 Customer Reference Design is also available.
Please refer to “Ordering Information” on page 90 for
complete ordering information.
2DS726A1
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. CHARACTERISTIC AND SPECIFICATION TABLES ......................................................................... 18
SPECIFIED OPERATING CONDITIONS ............................................................................................. 18
ABSOLUTE MAXIMUM RATINGS ....................................................................................................... 18
ANALOG INPUT CHARACTERISTICS ................................................................................................ 19
ADC DIGITAL FILTER CHARACTERISTICS ....................................................................................... 19
PWM POWER OUTPUT CHARACTERISTICS .................................................................................... 20
SERIAL AUDIO INPUT PORT SWITCHING SPECIFICATIONS ......................................................... 21
AUX SERIAL AUDIO I/O PORT SWITCHING SPECIFICATIONS ....................................................... 22
XTI SWITCHING SPECIFICATIONS .................................................................................................... 23
SYS_CLK SWITCHING SPECIFICATIONS ......................................................................................... 23
PWM_SIGX SWITCHING SPECIFICATIONS ...................................................................................... 23
I²C CONTROL PORT SWITCHING SPECIFICATIONS ....................................................................... 24
DC ELECTRICAL CHARACTERISTICS .............................................................................................. 25
DIGITAL INTERFACE SPECIFICATIONS ........................................................................................... 25
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 Recommended Power-Up Sequence ....................................................................... 28
6.1.2.2 Recommended Power-Down Sequence .................................................................. 28
6.1.3 Input Source Selection .......................................................................................................... 28
6.1.4 Digital Sound Processing ...................................................................................................... 29
6.1.4.1 Pre-Scaler ................................................................................................................. 29
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 Foldback ................................................................................................... 39
6.1.4.12 2-Way Crossover & Sensitivity Control ................................................................... 41
6.1.5 Auxiliary Serial Output .......................................................................................................... 42
6.1.6 Serial Audio Delay & Warning Input Port .............................................................................. 42
6.1.6.1 Serial Audio Delay Interface ..................................................................................... 42
6.1.6.2 External Warning Input Port ..................................................................................... 43
6.1.7 PWM Output Configuration ................................................................................................... 43
6.1.7.1 PWM Power Output Configurations .......................................................................... 43
6.1.7.2 PWM_SIG Logic-Level Output Configurations ......................................................... 44
6.1.7.3 PWM PopGuard Transient Control ........................................................................... 45
6.1.7.4 PWM Channel Delay ................................................................................................ 46
6.1.7.5 PWM AM Frequency Shift ........................................................................................ 47
6.1.8 Headphone Detection & Hardware Mute Input ..................................................................... 47
DS726A1
3
CS4525
6.1.9 Interrupt Reporting ................................................................................................................ 48
6.1.10 Automatic Power Stage Shut-Down ................................................................................... 48
6.2 Hardware Mode ............................................................................................................................. 49
6.2.1 System Clocking ................................................................................................................... 49
6.2.2 Power-Up and Power-Down ................................................................................................. 49
6.2.2.1 Recommended Power-Up Sequence ....................................................................... 49
6.2.2.2 Recommended Power-Down Sequence .................................................................. 49
6.2.3 Input Source Selection .......................................................................................................... 50
6.2.4 PWM Channel Delay ............................................................................................................ 50
6.2.5 Digital Signal Flow ................................................................................................................ 51
6.2.5.1 High-Pass Filter ........................................................................................................ 51
6.2.5.2 Mute Control ............................................................................................................. 51
6.2.5.3 Warning and Error Reporting .................................................................................... 51
6.2.6 Thermal Foldback ................................................................................................................. 52
6.2.7 Automatic Power Stage Shut-Down ..................................................................................... 53
6.3 PWM Modulators and Sample Rate Converters ............................................................................ 53
6.4 Output Filters ................................................................................................................................. 54
6.4.1 Half-Bridge Output Filter ....................................................................................................... 54
6.4.2 Full-Bridge Output Filter (Stereo or Parallel) ........................................................................ 55
6.5 Analog Inputs ................................................................................................................................. 56
6.6 Serial Audio Interfaces ................................................................................................................... 57
6.6.1 I²S Data Format .................................................................................................................... 57
6.6.2 Left-Justified Data Format .................................................................................................... 57
6.6.3 Right-Justified Data Format .................................................................................................. 58
6.7 I²C Control Port Description and Timing ........................................................................................ 59
7. PCB LAYOUT CONSIDERATIONS ..................................................................................................... 60
7.1 Power Supply, Grounding .............................................................................................................. 60
7.1.1 Integrated VD Regulator ....................................................................................................... 60
7.2 QFN Thermal Pad .......................................................................................................................... 60
8. REGISTER QUICK REFERENCE ........................................................................................................ 61
9. REGISTER DESCRIPTIONS ................................................................................................................ 64
9.1 Clock Configuration (Address 01h) ................................................................................................ 64
9.1.1 SYS_CLK Output Enable (EnSysClk) ................................................................................... 64
9.1.2 SYS_CLK Output Divider (DivSysClk) .................................................................................. 64
9.1.3 Clock Frequency (ClkFreq[1:0]) ............................................................................................ 64
9.1.4 HP_Detect/Mute Pin Active Logic Level (HP/MutePol) ......................................................... 65
9.1.5 HP_Detect/Mute Pin Mode (HP/Mute) .................................................................................. 65
9.1.6 Modulator Phase Shifting (PhaseShift) ................................................................................. 65
9.1.7 AM Frequency Shifting (FreqShift) ....................................................................................... 65
9.2 Input Configuration (Address 02h) ................................................................................................. 66
9.2.1 Input Source Selection (ADC/SP) ......................................................................................... 66
9.2.2 ADC High-Pass Filter Enable (EnAnHPF) ............................................................................ 66
9.2.3 Serial Port Sample Rate (SPRate[1:0]) - Read Only ............................................................ 66
9.2.4 Input Serial Port Digital Interface Format (DIF [2:0]) ............................................................ 66
9.3 AUX Port Configuration (Address 03h) .......................................................................................... 67
9.3.1 Enable Aux Serial Port (EnAuxPort) ..................................................................................... 67
9.3.2 Delay & Warning Port Configuration (DlyPortCfg[1:0]) ......................................................... 67
9.3.3 Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ) .................................................. 67
9.3.4 Aux Serial Port Right Channel Data Select (RChDSel[1:0]) ................................................. 67
9.3.5 Aux Serial Port Left Channel Data Select (LChDSel[1:0]) .................................................... 68
9.4 Output Configuration Register (Address 04h) ............................................................................... 68
9.4.1 Output Configuration (OutputCfg[1:0]) .................................................................................. 68
9.4.2 PWM Signals Output Data Select (PWMDSel[1:0]) .............................................................. 68
9.4.3 Channel Delay Settings (OutputDly[3:0]) .............................................................................. 68
4
DS726A1
CS4525
9.5 Foldback and Ramp Configuration (Address 05h) ......................................................................... 69
9.5.1 Enable Thermal Foldback (EnTherm) ................................................................................... 69
9.5.2 Lock Foldback Adjust (LockAdj) ........................................................................................... 69
9.5.3 Foldback Attack Delay (AttackDly[1:0]) ................................................................................ 69
9.5.4 Enable Foldback Floor (EnFloor) .......................................................................................... 70
9.5.5 Ramp Speed (RmpSpd[1:0]) ................................................................................................ 70
9.6 Mixer / Pre-Scale Configuration (Address 06h) ............................................................................. 70
9.6.1 Pre-Scale Attenuation (PreScale[2:0]) .................................................................................. 70
9.6.2 Right Channel Mixer (RChMix[1:0]) ...................................................................................... 70
9.6.3 Left Channel Mixer (LChMix[1:0]) ......................................................................................... 71
9.7 Tone Configuration (Address 07h) ................................................................................................. 71
9.7.1 De-Emphasis Control (DeEmph) .......................................................................................... 71
9.7.2 Adaptive Loudness Compensation Control (Loudness) ....................................................... 71
9.7.3 Digital Signal Processing High-Pass Filter (EnDigHPF) ....................................................... 71
9.7.4 Treble Corner Frequency (TrebFc[1:0]) ................................................................................ 72
9.7.5 Bass Corner Frequency (BassFc[1:0]) ................................................................................. 72
9.7.6 Tone Control Enable (EnToneCtrl) ....................................................................................... 72
9.8 Tone Control (Address 08h) ........................................................................................................... 72
9.8.1 Treble Gain Level (Treb[3:0]) ................................................................................................ 72
9.8.2 Bass Gain Level (Bass[3:0]) ................................................................................................. 73
9.9 2.1 Bass Manager/Parametric EQ Control (Address 09h) ............................................................. 73
9.9.1 Freeze Controls (Freeze) ...................................................................................................... 73
9.9.2 Bass Cross-Over Frequency (BassMgr[2:0]) ........................................................................ 73
9.9.3 Enable LFE Parametric EQ (EnLFEPEq) ............................................................................. 74
9.9.4 Enable Channel B Parametric EQ (EnChBPEq) ................................................................... 74
9.9.5 Enable Channel A Parametric EQ (EnChAPEq) ................................................................... 74
9.10 Volume and 2-Way Cross-Over Configuration (Address 55h) ..................................................... 75
9.10.1 Soft Ramp and Zero Cross Control (SZCMode[1:0]) ........................................................... 75
9.10.2 Enable 50% Duty Cycle for Mute Condition (Mute50/50) ..................................................... 75
9.10.3 Auto-Mute (AutoMute) .......................................................................................................... 75
9.10.4 Enable 2-Way Crossover (En2Way) .................................................................................... 76
9.10.5 2-Way Cross-Over Frequency (2WayFreq[2:0]) .................................................................. 76
9.11 Channel 1-2: 2-Way Sensitivity Control (Address 56h) ................................................................ 76
9.11.1 Channel 1 and Channel 2 Low-Pass Sensitivity Adjust (LowPass[3:0]) .............................. 76
9.11.2 Channel 1 and Channel 2 High-Pass Sensitivity Adjust (HighPass[3:0]) ............................. 77
9.12 Master Volume Control (Address 57h) ........................................................................................ 77
9.12.1 Master Volume Control (MVol[7:0]) ...................................................................................... 77
9.13 Channel 1, 2, & 3 Volume Control (Address 58h, 59h, & 5Ah) .................................................... 78
9.13.1 Channel X Volume Control (ChXVol[7:0]) ............................................................................ 78
9.14 Mute/Invert Control (Address 5Bh) .............................................................................................. 78
9.14.1 ADC Invert Signal Polarity (InvADC) .................................................................................... 78
9.14.2 Invert Signal Polarity (InvChX) ............................................................................................. 78
9.14.3 ADC Channel Mute (MuteADC) ........................................................................................... 78
9.14.4 Independent Channel Mute (MuteChX) ............................................................................... 79
9.15 Limiter Configuration 1 (Address 5Ch) ......................................................................................... 79
9.15.1 Maximum Threshold (Max[2:0]) ........................................................................................... 79
9.15.2 Minimum Threshold (Min[2:0]) ............................................................................................. 79
9.15.3 Peak Signal Limit All Channels (LimitAll) ............................................................................. 79
9.15.4 Peak Detect and Limiter Enable (EnLimiter) ........................................................................ 80
9.16 Limiter Configuration 2 (Address 5Dh) ......................................................................................... 80
9.16.1 Limiter Release Rate (RRate[5:0]) ....................................................................................... 80
9.17 Limiter Configuration 3 (Address 5Eh) ......................................................................................... 80
9.17.1 Limiter Attack Rate (ARate[5:0]) .......................................................................................... 80
9.18 Power Control (Address 5Fh) ...................................................................................................... 81
DS726A1
5
CS4525
9.18.1 Select VD Level (SelectVD) ................................................................................................. 81
9.18.2 Power Down ADC (PDnADC) .............................................................................................. 81
9.18.3 Power Down PWM Power Output X (PDnOutX) .................................................................. 81
9.18.4 Power Down (PDnAll) .......................................................................................................... 81
9.19 Interrupt Register (Address 60h) ................................................................................................. 82
9.19.1 SRC Lock State Transition Interrupt Bit (SRCLock) ............................................................. 82
9.19.2 ADC Overflow Interrupt Bit (ADCOvfl) ................................................................................. 82
9.19.3 Channel Overflow Interrupt Bit (ChOvfl) ............................................................................... 82
9.19.4 Amplifier Error Interrupt Bit (AmpErr) ................................................................................... 83
9.19.5 Mask Bit for SRC State (SRCLockM) ................................................................................... 83
9.19.6 Mask Bit for ADC Overflow (ADCOvflM) .............................................................................. 83
9.19.7 Mask Bit for Channel X Overflow (ChOvflM) ........................................................................ 84
9.19.8 Mask Bit for Amplifier Error (AmpErrM) ................................................................................ 84
9.20 Interrupt Status Register (Address 61h) - Read Only .................................................................. 84
9.20.1 SRC State Transition (SRCLockSt) ..................................................................................... 84
9.20.2 ADC Overflow (ADCOvfl) ..................................................................................................... 85
9.20.3 Channel X Overflow (ChXOvfl) ............................................................................................ 85
9.20.4 Ramp-Up Cycle Complete (RampDone) .............................................................................. 85
9.21 Amplifier Error Status (Address 62h) - Read Only ....................................................................... 85
9.21.1 Over-Current Detected On Channel X (OverCurrX) ............................................................. 85
9.21.2 External Amplifier State (ExtAmpSt) .................................................................................... 86
9.21.3 Under Voltage Detected (UnderV) ....................................................................................... 86
9.21.4 Thermal Error Detected (ThermErr) ..................................................................................... 86
9.21.5 Thermal Warning Detected (ThermWarn) ............................................................................ 86
9.22 Chip I.D. and Revision Register (Address 63h) - Read Only ....................................................... 87
9.22.1 Device Identification (DeviceID[4:0]) .................................................................................... 87
9.22.2 Device Revision (RevID[2:0]) ............................................................................................... 87
10. PARAMETER DEFINITIONS .............................................................................................................. 88
11. REFERENCES .................................................................................................................................... 88
12. PACKAGE DIMENSIONS .................................................................................................................. 89
13. THERMAL CHARACTERISTICS ....................................................................................................... 90
13.1 Thermal Flag ............................................................................................................................... 90
14. ORDERING INFORMATION .............................................................................................................. 90
15. REVISION HISTORY .......................................................................................................................... 91
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
Figure 16.Bi-Quad Filter Architecture ........................................................................................................ 33
Figure 17.Peak Signal Detection & Limiting .............................................................................................. 37
6
DS726A1
CS4525
Figure 18.Foldback Process ..................................................................................................................... 39
Figure 19.2-Channel Full-Bridge PWM Output Delay ............................................................................... 46
Figure 20.3-Channel PWM Output Delay .................................................................................................. 46
Figure 21.Typical SYS_CLK Input Clocking Configuration ....................................................................... 49
Figure 22.Hardware Mode PWM Output Delay ......................................................................................... 50
Figure 23.Hardware Mode Digital Signal Flow .......................................................................................... 51
Figure 24.Foldback Process ..................................................................................................................... 52
Figure 25.Output Filter - Half-Bridge ......................................................................................................... 54
Figure 26.Output Filter - Full-Bridge .......................................................................................................... 55
Figure 27.Recommended Unity Gain Input Filter ...................................................................................... 56
Figure 28.Recommended 2 VRMS Input Filter ........................................................................................... 56
Figure 29.I²S Serial Audio Formats ........................................................................................................... 57
Figure 30.Left-Justified Serial Audio Formats ........................................................................................... 57
Figure 31.Right-Justified Serial Audio Formats ......................................................................................... 58
Figure 32.Control Port Timing, I²C Write ................................................................................................... 59
Figure 33.Control Port Timing, I²C Read ................................................................................................... 59
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 .................................................................................................. 41
Table 6. Auxiliary Serial Port Data Output ................................................................................................ 42
Table 7. PWM Power Output Configurations ............................................................................................ 43
Table 8. PWM Logic-Level Output Configurations .................................................................................... 44
Table 9. PWM Output Switching Rates and Quantization Levels ............................................................. 47
Table 10. SYS_CLOCK Frequency Selection ........................................................................................... 49
Table 11. Input Source Selection .............................................................................................................. 50
Table 12. Serial Audio Interface Format Selection .................................................................................... 50
Table 13. Thermal Foldback Enable Selection ......................................................................................... 52
Table 14. PWM Output Switching Rates and Quantization Levels ........................................................... 53
Table 15. Low-Pass Filter Components - Half-Bridge ............................................................................... 54
Table 16. DC-Blocking Capacitors Values - Half-Bridge ........................................................................... 54
Table 17. Low-Pass Filter Components - Full-Bridge ............................................................................... 55
Table 18. Input Source Selection .............................................................................................................. 60
DS726A1
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 #
CS4525
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.
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
DS726A1
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 for shaping the output ramp time for 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
PWM Output (Output) - PWM switching signals.
DLY_SDOUT
41
Delay Serial Audio Data Out (Output) - Output for two’s complement serial audio data. Default pin
configuration.
DLY_SDIN/
EX_TWR
42
Delay Serial Audio Data Input (Input) - Input for two’s complement serial audio data. Default pin
configuration.
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.
XTO
47
Crystal Oscillator Output (Output) - Crystal oscillator driver output.
XTI
48
Crystal Oscillator Input (Input) - Crystal oscillator driver input.
DS726A1
9
CS4525
Pin Name
TSTI
TSTO
SYS_CLK
I2S/LJ
EN_TFB
ERROC
ERRUVTE
TWR
PWM_SIG1
PWM_SIG2
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
CS4525
18
19
AGND
FILT+
VQ
AFILTL
AFILTR
AINL
Pin #
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.
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) - Mute input signal.
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
DS726A1
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) - Used for shaping the output ramp time for 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
PWM Output (Output) - PWM switching signals.
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
and output ports. 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.
DS726A1
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
Pin Name
I/O
Driver
Receiver
1
INT
Output
2.5 V-5.0 V, Open Drain
2
SCL
Input
-
2.5 V-5.0 V, with Hysteresis
3
SDA
Input/Output
2.5 V-5.0 V, Open Drain
2.5 V-5.0 V, with Hysteresis
7
HP_DETECT
MUTE
Input
Input
-
2.5 V-5.0 V
2.5 V-5.0 V
41
DLY_SDOUT
Output
2.5 V-5.0 V, CMOS
-
42
DLY_SDIN
EX_TWR
Input
Input
-
2.5 V-5.0 V
2.5 V-5.0 V
43
AUX_SDOUT
Output
2.5 V-5.0 V, CMOS
-
44
AUX_SCLK
Output
2.5 V-5.0 V, CMOS
-
45
AUX_LRCK
Output
2.5 V-5.0 V, CMOS
-
1
SEL_OSC0
Input
-
2.5 V-5.0 V
2
SEL_OSC1
Input
-
2.5 V-5.0 V
3
ADC/SP
Input
-
2.5 V-5.0 V
Software Mode
VD
Hardware Mode
VD
7
MUTE
Input
-
2.5 V-5.0 V
41
TWR
Output
2.5 V-5.0 V, Open Drain
-
42
ERRUVTE
Output
2.5 V-5.0 V, Open Drain
-
43
ERROC
Output
2.5 V-5.0 V, Open Drain
-
44
EN_TFB
Input
-
2.5 V-5.0 V
45
I²S/LJ
Input
-
2.5 V-5.0 V
4
LRCK
Input
-
2.5 V-5.0 V
5
SCLK
Input
-
2.5 V-5.0 V
6
SDIN
Input
-
2.5 V-5.0 V
8
RST
Input
-
2.5 V-5.0 V
9
LVD
Input
-
2.5 V-5.0 V
All Modes
VD
SYS_CLK
Input/Output
2.5 V-5.0 V, CMOS
2.5 V-5.0 V
VD_REG
46
PWM_SIG1
Output
2.5 V, CMOS
-
PWM_SIG2
Output
2.5 V, CMOS
-
VP
OUT1-OUT4
Output
10.5 V-18.0 V Power MOSFET
-
Table 1. I/O Power Rails
12
DS726A1
CS4525
3. TYPICAL CONNECTION DIAGRAMS
+10.5 V to +18 V
+3.3 to +5 V
10 µF 0.1 µF
470 µF
12
0.1 µF
25
0.1 µF
30
0.1 µF
31
0.1 µF
470 µF
36
Analog
Audio
Inputs
VP
VP
VP
VD
VP
0.033 µF
RAMP_CAP 35
Analog
Audio
Switch
19
AINL
20
AINR
OUT1 35
OUT2 32
Analog
Monitor
Output
Output
Filter
CS4525
Crystal
48
XTI
24.576 MHz
47
XTO
OUT3 29
OUT4 26
MPEG
Audio
Processor
- or HDMI
Receiver
Lip-Synch
Delay
46
SYS_CLK
5
SCLK
4
LRCK
6
SDIN
7
HP_DETECT/MUTE
43
AUX_SDOUT
45
AUX_LRCK
44
AUX_SCLK
41
DLY_SDOUT
42
DLY_SDIN
NJU26902
+2.5V
11
Line
Output
PWM_SIG1 40
- or Headphone
Output
PWM_SIG2 39
LVD
9
OCREF 21
10 µF
Output
Filter
22 kΩ
VD or GND
20 kΩ
VD_REG
FILT+ 15
0.1 µF
VA_REG 13
0.1 µF
10 µF
10 µF
150 pF
150 pF
1 µF
2 kΩ*
AGND 14
2
SCL
3
SDA
1
INT
8
RST
AFILTA 17
AFILTB 18
D
PG
N
PG
N
D
PG
N
D
PG
N
D
D
N
D
PG
N
PG
D
PG
N
10
PG
N
D
G
N
*Note: Resistors are required for
I²C control port operation.
D
VQ 16
D
MicroController
2 kΩ*
22 kΩ
VD
22
23
27
28
33
34
37
38
Figure 1. Typical Connection Diagram - Software Mode
DS726A1
13
CS4525
+10.5 V to +18 V
+3.3 to +5 V
10 µF 0.1 µF
470 µF
12
0.1 µF
25
0.1 µF
30
0.1 µF
31
0.1 µF
470 µF
36
Analog
Audio
Inputs
VP
VP
VP
VD
VP
0.033 µF
RAMP_CAP 35
Analog
Audio
Switch
19
AINL
20
AINR
OUT1 35
OUT2 32
Analog
Monitor
Output
Output
Filter
CS4525
Audio
Processor
Clock
18.432 MHz
5
SCLK
4
LRCK
OUT3 29
OUT4 26
6
SDIN
46
SYS_CLK
1
CLK_FREQ0
2
CLK_FREQ1
Output
Filter
Line
Output
PWM_SIG1 40
- or -
MicroController
Headphone
Output
PWM_SIG2 39
22 kΩ
22 kΩ
22 kΩ
VD
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
9
OCREF 21
22 kΩ
VD or GND
20 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
DS726A1
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
Analog
Out
Gate
Drive
Left
Speaker
Gate
Drive
Gate
Drive
Right
Speaker
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
CS4412
PWM In
Gate
Drive
Gate
Drive
Subwoofer
Gate
Drive
Status
Out
Gate
Drive
Figure 4. Typical System Configuration 2
DS726A1
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
Analog
Out
Gate
Drive
Gate
Drive
Left
Speaker
Gate
Drive
SYS_CLK
Gate
Drive
Power
Foldback
PWM_SIG1
PWM_SIG2
CS4412
PWM In
Gate
Drive
Gate
Drive
Right
Speaker
Gate
Drive
Status
Out
Gate
Drive
CS4412
PWM In
Gate
Drive
Gate
Drive
Subwoofer
Gate
Drive
Status
Out
Gate
Drive
Figure 5. Typical System Configuration 3
16
DS726A1
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
Delay
Port
Clock
Out
Analog
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
DS726A1
17
CS4525
5. CHARACTERISTIC AND SPECIFICATION TABLES
(All Min/Max characteristics and specifications are guaranteed over the Specified Operating Conditions. Typical
performance characteristics and specifications are derived from measurements taken at nominal supply voltages
and TA = 25° C.)
SPECIFIED OPERATING CONDITIONS
(AGND = DGND=PGND=0 V, all voltages with respect to ground.)
Parameters
Symbol
Min
Nom
Max
Units
DC Power Supply
Digital and Analog Core
Amplifier Outputs
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
10.5
-
18.0
V
TA
-10
-
+70
°C
-
+150
°C
Temperature
Ambient Temperature
Commercial
Junction Temperature
TJ
ABSOLUTE MAXIMUM RATINGS
(AGND = DGND = PGND = 0 V; all voltages with respect to ground.)
Parameters
DC Power Supply
Symbol
Min
Max
Units
PWM Outputs
Digital and Analog Core
VP
VD
-0.3
-0.3
20.0
6.0
V
V
(Note 2)
Iin
-
±10
mA
Input Current
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
Ambient Operating Temperature - Power Applied
Commercial
Storage Temperature
Notes:
1. Operation at or beyond these limits may result in permanent damage to the device.
Normal operation is not guaranteed at these extremes.
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
DS726A1
CS4525
ANALOG INPUT CHARACTERISTICS
Test Conditions (unless otherwise specified): Input Signal: 1 kHz sine wave through the recommended passive
input filter shown in Figure 27 on page 56; 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
Analog In to ADC
Dynamic Range (Note 4)
A-weighted
unweighted
-1 dB
-20 dB
-60 dB
Total Harmonic Distortion + Noise
DC Accuracy
Interchannel Gain Mismatch
Gain Drift
Input
Interchannel Isolation
Full-scale Input Voltage
Input Impedance
Notes:
(Note 5)
Min
Typ
Max
Unit
90
87
-
95
92
-88
-75
-35
-82
-
dB
dB
dB
dB
dB
-
0.1
±100
-
dB
ppm/°C
1.96
40
90
2.18
-
2.40
-
dB
Vpp
kΩ
4. Referred to the typical full-scale voltage.
5. Measured between AINx and AGND.
ADC DIGITAL FILTER CHARACTERISTICS
Parameter
Passband (Frequency Response) (Note 6)
Min
Typ
Max
Unit
0
-
0.4948
Fs
-0.09
-
0
dB
-
-
Fs
48.4
-
-
dB
-
2.7/Fs
-
s
-3.0 dB
-0.13 dB
-
3.7
24.2
-
Hz
Hz
20 Hz
-
10
-
Deg
-
-
0.17
dB
-
105/Fs
0
s
to -0.1 dB corner
Passband Ripple
Stopband
(Note 6) 0.6677
Stopband Attenuation
Total Group Delay
High-Pass Filter Characteristics
Frequency Response
Phase Deviation
Passband Ripple
Filter Settling Time
Notes:
DS726A1
6. 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.
19
CS4525
PWM POWER OUTPUT CHARACTERISTICS
AGND = DGND = PGND = 0 V; All voltages with respect to ground; VP = 18 V; RL = 8 Ω for full-bridge, RL = 4 Ω for
half-bridge and parallel full-bridge; PWM Switch Rate = 384 kHz; 10 Hz to 20 kHz Measurement Bandwidth; Performance measurements taken with a full scale 997 Hz sine wave and AES17 filter; Unless otherwise specified.
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
-
0.1
0.3
0.1
0.3
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
102
99
102
99
-
dB
dB
dB
dB
dB
dB
RDS(ON)
Id = 0.5 A, TJ = 50°C
-
518
615
mΩ
h
PO = 2 x 11.3 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
Rise Time of OUTx
Fall Time of OUTx
PWmin
No Load
-
50
-
ns
tr
Resistive Load
-
20
-
ns
tf
Resistive Load
-
20
-
ns
PWM Output Over-Current Error Trip Point
ICE
TA = 25°C, OCREF = 20 kΩ
2.0
-
-
A
Junction Thermal Warning Trip Point
TTW
-
120
-
°C
Junction Thermal Error Trip Point
TTE
-
140
-
°C
VP Under-Voltage Error Trip Point
VUV
TA = 25°C
4
-
-
V
Ramp-Up Time - Half-Bridge Configuration
TRU
Capacitor = 1000 µF
-
0.8
-
s
Ramp-Down Time- Half-Bridge Configuration
TRD
Capacitor = 1000 µF
-
50
-
s
20
DS726A1
CS4525
SERIAL AUDIO INPUT PORT SWITCHING SPECIFICATIONS
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
%
-
-
128•FSI
64•FSI
Hz
Hz
Supported Input Sample Rates
LRCK Duty Cycle
SCLK Frequency
Single-Speed Mode
Double-Speed Mode
1/tp
SCLK Duty Cycle
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
SDIN Hold Time After SCLK Rising Edge
RST pin Low Pulse Width
Notes:
(Note 7)
7. 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
DS726A1
21
CS4525
AUX SERIAL AUDIO I/O PORT SWITCHING SPECIFICATIONS
Inputs: Logic 0 = DGND; Logic 1 = VD; AUX_SDOUT & DLY_SDOUT CL = 15 pF. (Note 8)
Parameters
Symbol
Min
Typ
Max
Units
FSO
-
FCLK/384
FCLK/512
FCLK/512
-
Hz
Hz
Hz
-
50
-
%
-
1/FSO
-
s
-
48•FSO
64•FSO
64•FSO
-
Hz
Hz
Hz
Input Source: Analog Inputs (Internal ADC)
Output Sample Rate
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
AUX_LRCK Duty Cycle
AUX_LRCK Period
AUX_SCLK Frequency
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’ FSCLKO
ClkFreq[1:0] = ‘10’
AUX_SCLK Duty Cycle
-
50
-
%
AUX_SCLK Period
-
1/FSCLKO
-
s
-
FSI
FSI/2
-
Hz
Hz
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 10)
AUX_LRCK Period
AUX_SCLK Frequency
(Note 11)
FSO
(Note 9, 10)
FS-In = 32kHz, 44.1 kHz, 48 kHz
FS-In = 96 kHz
AUX_SCLK Duty Cycle
AUX_SCLK Period
(Note 10, 11)
FS-In = 32kHz, 44.1 kHz, 48 kHz
FS-In = 96 kHz
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
Input Source: Analog Inputs or Serial Audio Input Port
AUX_LRCK Rising Edge to AUX_SCLK Falling Edge
tLTSF
-
-
20
ns
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:
8. FCLK is the frequency of the applied crystal or the input SYS_CLK signal. TCLK = 1/FCLK.
9. FSI is the frequency of the input LRCK signal. TSI = 1/FSI
10. May vary during normal operation.
11. FSCLKI is the frequency of the input SCLK signal. TSCLKI = 1/FSCLKI.
AUX_LRCK
AUX_SCLK
tLTSF
tSRDV
AUX_SDOUT
DLY_SDOUT
LSB
MSB
tDISU
DLY_SDIN
LSB
MSB - 1
tDIH
MSB
MSB - 1
Figure 8. AUX Serial Port Interface Master Mode Timing
22
DS726A1
CS4525
XTI SWITCHING SPECIFICATIONS
Parameter
External Crystal Operating Frequency
(Note 12)
Symbol
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
Min
Typ
Max
Unit
17.510
23.347
25.650
18.432
24.576
27.000
19.354
25.805
28.350
MHz
MHz
MHz
45
50
55
%
XTI Duty Cycle
Notes:
12. See “Clock Frequency (ClkFreq[1:0])” on page 64.
SYS_CLK SWITCHING SPECIFICATIONS
Input: Logic 0 = DGND; Logic 1 = VD, SYS_CLK Output: CL = 20 pF.
Parameter
External Clock Operating Frequency
(Note 12)
Symbol
ClkFreq[1:0] = ‘00’
ClkFreq[1:0] = ‘01’
ClkFreq[1:0] = ‘10’
Rising Edge RST to start of SYS_CLK
tsclko
SYS_CLK Period
tsclki
Min
Typ
Max
Unit
17.510
23.347
25.650
18.432
24.576
27.000
19.354
25.805
28.350
MHz
MHz
MHz
1024*tsclki
SYS_CLK Duty Cycle
37.04
---
54.25
ns
45
50
55
%
SYS_CLK high time
tclkih
16.67
---
29.84
ns
SYS_CLK low time
tclkil
16.67
---
29.84
ns
Typ
Max
Unit
SYS_CLK
(output)
tsclko
___
RST
Figure 9. SYS_CLK Timing from Reset
PWM_SIGX SWITCHING SPECIFICATIONS
Parameter
PWM_SIGx Period
Symbol
Min
tpwm
2.60
-
1.18
µs
Rise Time of PWM_SIGx
tr
-
2.1
-
ns
Fall Time of PWM_SIGx
tf
-
1.4
-
ns
tr
tf
PWM_SIGx
tpwm
Figure 10. PWM_SIGX Timing
DS726A1
23
CS4525
I²C CONTROL PORT SWITCHING SPECIFICATIONS
Inputs: Logic 0 = DGND; Logic 1 = VD; SDA CL = 30 pF
Parameter
Symbol
Min
Max
Unit
SCL Clock Frequency
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
tsust
4.7
-
µs
thdd
0
-
µs
tsud
250
-
ns
trc
-
1
µs
Setup Time for Repeated Start Condition
SDA Hold Time from SCL Falling
(Note 13)
SDA Setup time to SCL Rising
Rise Time of SCL and SDA
Fall Time SCL and SDA
tfc
-
300
ns
Setup Time for Stop Condition
tsusp
4.7
-
µs
Acknowledge Delay from SCL Falling
tack
300
1000
ns
Notes:
13. 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
DS726A1
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
Normal Operation
Typ
Max
Units
(Note 14)
Power Supply Current
VD = 3.3 V
-
20
-
mA
Power Dissipation
VD = 3.3 V
-
66
-
mW
-
4.3
-
mA
2.25
-
2.5
-
2.75
3
V
mA
2.25
-
2.5
-
2.75
1
V
mA
-
0.5•VA_REG
23
-
10
V
kΩ
µA
-
VA_REG
-
V
-
60
40
-
dB
dB
Power-Down Mode
(Note 15)
Power Supply Current
VD = 3.3 V
VD_REG Characteristics
Nominal Voltage
DC current source
VA_REG Characteristics
Nominal Voltage
DC current source
VQ Characteristics
Nominal Voltage
Output Impedance
DC current source/sink
(Note 16)
Filt+ Nominal Voltage
Power Supply Rejection Ratio (Note 17)
Notes:
1 kHz
60 Hz
14. Normal operation is defined as RST = HI.
15. Power-Down Mode is defined as RST = LOW with all input lines held static.
16. The DC current drain represents the allowed current from the VQ pin due to typical leakage through
the electrolytic de-coupling capacitors.
17. 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
0.7*VD_REG
VD
V
Low-Level Input Voltage
VIL
-
0.20*VD_REG
V
High-Level Output Voltage
Io=2 mA
VOH
0.90*VD
-
V
Low-Level Output Voltage
Io=2 mA
VOL
-
0.2
V
-
±10
uA
-
8
pF
Input Leakage Current
Input Capacitance
DS726A1
Iin
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 59.
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 immediately after 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.
Referenced Control
Register Location
ClkFreq[1:0]......................... “Clock Frequency (ClkFreq[1:0])” on page 64
PDnAll ................................. “Power Down (PDnAll)” on page 81
6.1.1.1
SYS_CLK Input Clock Mode
If an input clock is detected on the SYS_CLK pin and oscillations are not detected on the XTI 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
DS726A1
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.
If an external crystal is connected to the XTI/XTO pins following the release of RST, the device will automatically use the crystal as its clock source regardless of the presence of an input clock signal on the
SYS_CLK pin.
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.
Figure 13 below demonstrates a typical clocking configuration using the crystal oscillator.
Reset
RST
RST
CS4525
DSP
XTI
XTO
SYS_CLK
Clock_In
Figure 13. Typical Crystal Oscillator Clocking Configuration
Referenced Control
Register Location
EnSysClk............................. “SYS_CLK Output Enable (EnSysClk)” on page 64
DivSysClk............................ “SYS_CLK Output Divider (DivSysClk)” on page 64
DS726A1
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
Recommended 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 is connected to 2.5 V, clear the SelectVD bit in the Power Ctrl register
to indicate the 2.5 V VD supply level.
5. The desired register settings can be loaded while keeping the PDnAll bit set.
6. Clear the PDnAll bit to initiate the power-up sequence.
6.1.2.2
Recommended Power-Down Sequence
1. Set the PDnAll bit to power-down the device while eliminating audible pops.
2. Bring RST low to bring the device’s power consumption to an absolute minimum.
3. Remove power.
Referenced Control
Register Location
PDnAll ................................. “Power Down (PDnAll)” on page 81
LVD ..................................... “Select VD Level (SelectVD)” on page 81
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 57. Analog audio input
signals are supplied through the internal ADC as outlined in “Analog Inputs” on page 56. 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 66
DIF[2:0] ............................... “Input Serial Port Digital Interface Format (DIF [2:0])” on page 66
EnAnHPF ............................ “ADC High-Pass Filter Enable (EnAnHPF)” on page 66
28
DS726A1
CS4525
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
PWM
Output
Config
2-Ch Mixer
2.1 Bass Mgr
Ch. 3
Linkwitz-Riley
Crossover
Auxiliary
Serial Port
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
LFE
Param EQ 4 - 5
Loudness
Ch. A HPF
Ch. A LPF
Ch. B HPF
Ch. B LPF
Sensitivity
X-Over
Limiter
Ch. B
Master Vol Control
Ch. A
Ch. Vol Control
Bass Manager
Treble Tone Ctrl
Param. EQ 1 - 3
Bass Tone Ctrl
Ch. A
Mixer
De-Emphasis
Right
Ch. B
Serial Audio
Data In
High-Pass Filter
Left
Pre-Scaler
Foldback
Ch. A HPF
Ch. 1
Ch. A LPF
Ch. 2
Ch. 3
Ch. B HPF
Aux Serial Data Select
Ch. B LPF
Data to
Aux Port
Figure 14. Digital Signal Flow
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 70
DS726A1
29
CS4525
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 71
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 headphone 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 71
RChMix[1:0] ........................ “Right Channel Mixer (RChMix[1:0])” on page 70
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 65
30
DS726A1
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
Normalized to Fs
F2
0.24059 Fs
0.12030 Fs
Figure 15. De-Emphasis Filter
Referenced Control
Register Location
DeEmph .............................. “De-Emphasis Control (DeEmph)” on page 71
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
DS726A1
31
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 72
TrebFc[1:0] .......................... “Treble Corner Frequency (TrebFc[1:0])” on page 72
BassFc[1:0] ......................... “Bass Corner Frequency (BassFc[1:0])” on page 72
Treble[3:0] ........................... “Treble Gain Level (Treb[3:0])” on page 72
Bass[3:0] ............................. “Bass Gain Level (Bass[3:0])” on page 73
32
DS726A1
CS4525
6.1.4.6
Parametric EQ
The CS4525 implements 5 fully programmable parametric EQ filters. Three of the filters are 2-channel
filters dedicated to the channel A/B pair, and the remaining two are single-channel filters dedicated to the
LFE channel generated by the bass manager.
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] - a1x[n-1] - a2x[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 -3.99996 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 61 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.
Parametric equalizers 1, 2, and 3 can be independently enabled and disabled for channel A and B with
the EnChAPEq and EnChBPEq bits located in the EQ Config register. The EnLFEPEq bit in the same register enables and disables parametric equalizers 4 and 5 for the LFE channel.
Referenced Control
Register Location
EnChAPEq .......................... “Enable Channel A Parametric EQ (EnChAPEq)” on page 74
EnChBPEq .......................... “Enable Channel B Parametric EQ (EnChBPEq)” on page 74
EnLFEPEq .......................... “Enable LFE Parametric EQ (EnLFEPEq)” on page 74
DS726A1
33
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 71
EnToneCtrl .......................... “Tone Control Enable (EnToneCtrl)” on page 72
TrebFc[1:0] .......................... “Treble Corner Frequency (TrebFc[1:0])” on page 72
BassFc[1:0] ......................... “Bass Corner Frequency (BassFc[1:0])” on page 72
Treble[3:0] ........................... “Treble Gain Level (Treb[3:0])” on page 72
Bass[3:0] ............................. “Bass Gain Level (Bass[3:0])” on page 73
34
DS726A1
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 LFE 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 LFE 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 73
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 65
DS726A1
35
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 3 individual volume and muting controls, each
permanently assigned to one channel within the device.
Each channel has a corresponding Ch X Vol register used to gain or attenuate the channel from +24 dB
to -103 dB in 0.5 dB steps. Each output can be independently muted via the MuteChX bits in the Mute
Control register.
Master control allows the volume of all channels to be changed simultaneously by offsetting each channel’s individual volume setting by +24 dB to -103 dB in 0.5 dB steps. 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 exact 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
Ch X Vol .............................. “Channel 1, 2, & 3 Volume Control (Address 58h, 59h, & 5Ah)” on page 78
Master Vol ........................... “Master Volume Control (Address 57h)” on page 77
Mute50/50 ........................... “Enable 50% Duty Cycle for Mute Condition (Mute50/50)” on page 75
AutoMute............................. “Auto-Mute (AutoMute)” on page 75
SZCMode ............................ “Soft Ramp and Zero Cross Control (SZCMode[1:0])” on page 75
36
DS726A1
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.
DS726A1
37
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 register.
Referenced Control
Register Location
EnLimiter ............................. “Peak Detect and Limiter Enable (EnLimiter)” on page 80
LimitAll................................. “Peak Signal Limit All Channels (LimitAll)” on page 79
Max[2:0] .............................. “Maximum Threshold (Max[2:0])” on page 79
Min[2:0] ............................... “Minimum Threshold (Min[2:0])” on page 79
ARate[5:0] ........................... “Limiter Attack Rate (ARate[5:0])” on page 80
RRate[5:0] ........................... “Limiter Release Rate (RRate[5:0])” on page 80
38
DS726A1
CS4525
6.1.4.11
Thermal Foldback
The CS4525 implements comprehensive thermal foldback features to guard against damaging thermal
overload conditions.
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 trip 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
DS726A1
39
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 43 for
more information.
Referenced Control
Register Location
EnTherm ............................. “Enable Thermal Foldback (EnTherm)” on page 69
AttackDly[1:0] ...................... “Foldback Attack Delay (AttackDly[1:0])” on page 69
EnFloor................................ “Enable Foldback Floor (EnFloor)” on page 70
LockAdj ............................... “Lock Foldback Adjust (LockAdj)” on page 69
40
DS726A1
CS4525
6.1.4.12
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 is used can be 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 1 and channel 2 low- and
high-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 76
2WayFreq[2:0]..................... “2-Way Cross-Over Frequency (2WayFreq[2:0])” on page 76
HighPass[3:0]...................... “Channel 1 and Channel 2 High-Pass Sensitivity Adjust (HighPass[3:0])” on page 77
LowPass[3:0]....................... “Channel 1 and Channel 2 Low-Pass Sensitivity Adjust (LowPass[3:0])” on page 76
DS726A1
41
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 1 and 2 on the auxiliary output data channels 1 and 2 respectively.
LChDSel[1:0]
00
01
10
11
Aux Left Channel Data
Channel A
Channel B
LFE Channel
Channel B X-Over HPF
RChDSel[1:0]
00
01
10
11
Aux Right Channel Data
Channel A
Channel B
LFE Channel
Channel B X-Over LPF
Table 6. Auxiliary Serial Port Data Output
The data output on each channel is set by the LChDSel[1:0] and RChDSel[1:0] bits in the Aux Port Configuration register. The auxiliary port can be enabled using the EnAuxPort bit in the same register. When
enabled, the port operates as a master and clocks out data in the format dictated by the AuxI²S/LJ bits.
When disabled, the AUX_LRCK, AUX_SCLK, and AUX_SDOUT pins continuously drive a logic ‘0’.
Referenced Control
Register Location
EnAuxPort ........................... “Enable Aux Serial Port (EnAuxPort)” on page 67
LChDSel[1:0]....................... “Aux Serial Port Left Channel Data Select (LChDSel[1:0])” on page 68
RChDSel[1:0] ...................... “Aux Serial Port Right Channel Data Select (RChDSel[1:0])” on page 67
AuxI²S/LJ............................. “Aux/Delay Serial Port Digital Interface Format (AuxI²S/LJ)” on page 67
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 67
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
42
DS726A1
CS4525
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 67
EnAuxPort ........................... “Enable Aux Serial Port (EnAuxPort)” on page 67
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 in 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 39 for more information.
Referenced Control
Register Location
EnTherm ............................. “Enable Thermal Foldback (EnTherm)” on page 69
6.1.7
PWM Output Configuration
The CS4525 supports flexible PWM output configurations to enable a wide variety of system implementations. The 3 internal modulators can be used to generate multiple power output configurations and a
number of independently selected logic-level PWM output channel combinations. PWM PopGuard is
available for pop-free power up in half-bridge configurations, and PWM signal delays may be inserted to
manage system switching noise.
6.1.7.1
PWM Power Output Configurations
Three PWM power output configurations are supported as shown in Table 7 below. The configurations
support stereo full-bridge, stereo half-bridge with full-bridge LFE, 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 +
Channel 3 +
Channel 3 Channel 1 +
Channel 1 -
Output Pin(s)
OUT1
OUT2
OUT3
OUT4
OUT1
OUT2
OUT3
OUT4
OUT1, OUT2
OUT3, OUT4
Table 7. PWM Power Output Configurations
DS726A1
43
CS4525
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 signal on channels 1, 2, and 3 is 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 68
PDnAll ................................. “Power Down (PDnAll)” on page 81
6.1.7.2
PWM_SIG Logic-Level Output Configurations
Four channel mapping output configurations are supported for the PWM_SIG output pins as shown in
Table 8 below. The configurations support stereo, channel 1 with LFE, and channel 2 with LFE. When
disabled, the PWM_SIG pins continuously drive a logic ‘0’. The configurations are selected by the PWMDSel[1:0] bits in the Output Cfg register
PWMDSel[1:0]
00
01
10
11
PWM_SIG1
Output disabled.
Channel 1
Channel 1
Channel 2
PWM_SIG2
Output disabled.
Channel 2
Channel 3
Channel 3
Table 8. 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 is affected by the active state of the headphone detection input signal. In this configuration, the PWM_SIG1 and PWM_SIG2 output pins will output audio from
channel 1 and channel 2 respectively regardless of the setting of the PWMDSel[1:0] bits when the headphone detection input is active. When the headphone detection input signal becomes inactive, the PWM
logic-level outputs will be automatically reconfigured to the channel mapping dictated by the PWMDSel[1:0] bits. See the Headphone Detection & Hardware Mute Input section on page 47 for more information.
It should be noted that signal on channels 1, 2, and 3 is 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 68
HP/Mute .............................. “HP_Detect/Mute Pin Mode (HP/Mute)” on page 65
PDnAll ................................. “Power Down (PDnAll)” on page 81
44
DS726A1
CS4525
6.1.7.3
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.
PWM PopGuard 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 charged and
discharged.
The PWM PopGuard output ramp time can be varied from approximately 0.70 seconds to approximately
0.85 seconds and can be completely disabled via the RmpSpeed[1:0] bits in the Foldback Cfg register.
All output channels are affected by the RmpSpeed[1:0] bits, and PWM PopGuard is disabled by default.
Referenced Control
Register Location
RmpSpeed[1:0] ................... “Ramp Speed (RmpSpd[1:0])” on page 70
PDnAll ................................. “Power Down (PDnAll)” on page 81
PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 81
DS726A1
45
CS4525
6.1.7.4
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 19 below.
OUT1
OUT2
tchdly
OUT3
OUT4
Figure 19. 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 20 below.
OUT1
tch dly
OUT2
tch dly
OUT3
OUT4
Figure 20. 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 68
46
DS726A1
CS4525
6.1.7.5
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
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 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 9 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 9. 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 53.
Referenced Control
Register Location
FreqShift.............................. “AM Frequency Shifting (FreqShift)” on page 65
6.1.8
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 will output audio from channel 1 and channel 2 respectively regardless of the setting of the PWMDSel[1:0] bits; see “PWM_SIG Logic-Level Output Configurations” on
page 44 for more information. The OUT1 - OUT4 PWM driver outputs will mute by outputting a non-modulated 50% duty cycle signal. If the Ch1Mix[1:0] bits are configured for a mono mix on channel 1, the mix
will be disabled and channel 1 will be output on PWM_SIG1 while the headphone detect input signal is
active; see “Channel Mixer” on page 30 for more information. If the bass manager is enabled, it will be
automatically disabled while the headphone detect input signal is active; see “Bass Management” on
page 35 for more information.
When configured as a headphone detect input pin and the input is inactive, the OUT1 - OUT4 driver outputs will output audio according to the channel mixer and bass manager registers settings, and the
PWM_SIG output pins will mute by outputting a non-modulated 50% duty cycle.
In both 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 65
HP/MutePol ......................... “HP_Detect/Mute Pin Active Logic Level (HP/MutePol)” on page 65
PWMDSel[1:0]..................... “PWM Signals Output Data Select (PWMDSel[1:0])” on page 68
DS726A1
47
CS4525
6.1.9
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, it’s 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 Register (Address 60h)” on page 82
Int Status Register............... “Interrupt Status Register (Address 61h) - Read Only” on page 84
Amp Error Register ............. “Amplifier Error Status (Address 62h) - Read Only” on page 85
6.1.10
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 trip 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, the PDnAll bit in the Power Ctrl register must be set and then cleared to
resume normal device operation.
Referenced Control
Register Location
PDnAll ................................. “Power Down (PDnAll)” on page 81
48
DS726A1
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 ClkFreq[1:0] hardware control pins. These pins must be set to the appropriate
level before the RST signal is released to initiate a power-up sequence. The nominal clock frequencies
indicated by the states of the ClkFreq[1:0] pins are shown in Table 10 below. See the SYS_CLK Switching
Specifications table on page 23 for complete input frequency range specifications.
ClkFreq1
Low
Low
High
High
ClkFreq0
Low
High
Low
High
Nominal SYS_CLK Frequency
18.432 MHz
24.576 MHz
27.000 MHz
Reserved
Table 10. SYS_CLOCK Frequency Selection
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 21. 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
Recommended Power-Up Sequence
1. Hold RST low until the power supplies and the input SYS_CLK signal are stable.
2. Bring RST high.
Hardware mode will be entered after approximately 10 ms.
6.2.2.2
Recommended 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. Remove power.
DS726A1
49
CS4525
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 57. Analog audio input
signals are supplied through the internal ADC as outlined in “Analog Inputs” on page 56. The input source
is selected by the ADC/SP pin as shown in Table 11 below and can be changed at any time without causing any audible pops or clicks.
ADC/SP
Low
High
Selected Input Source
Digital Audio Inputs (Serial Port)
Analog Audio Inputs (ADC)
Table 11. 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 12 below.
I2S/LJ
Low
High
Selected Serial Audio Interface Format
Left-Justified
I²S
Table 12. 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 22 below. The absolute delay time is calculated by multiplying the period SYS_CLK by 4.
OUT1
OUT2
4 x TSYS_CLK
OUT3
OUT4
Figure 22. Hardware Mode PWM Output Delay
50
DS726A1
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. To protect against over-temperature conditions, thermal foldback is included for the internal power
stages.
The digital signal flow is shown in Figure 14 below.
MUTE
Serial Audio
Input Port
Serial Audio
Clocks & Data
Sample
Rate
Converter
PWM
Modulator
Sample
Rate
Converter
PWM
Modulator
Mute
Multi-Bit
∆Σ ADC
High-Pass
Stereo
Analog In
Foldback Attenuator
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 23. 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 an
exact non-modulated 50% duty cycle 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 available in software mode are disabled 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 or thermal error condition.
The trip 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.
DS726A1
51
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 trip 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 24. 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 13 below.
EN_TFB
Low
High
Selected Thermal Foldback Enable State
Thermal foldback disabled.
Thermal foldback enabled.
Table 13. Thermal Foldback Enable Selection
52
DS726A1
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 trip 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, 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 3 pairs of PWM modulators and sample rate converters, each clocked from the external crystal or system clock applied at power-up. All 3 modulator and sample rate converter pairs are available in software mode (see Figure 14 on page 29), and 2 pairs are used in hardware mode (see Figure 23
on page 51).
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 14
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 14. PWM Output Switching Rates and Quantization Levels
DS726A1
53
CS4525
6.4
Output Filters
The filter placed after the PWM outputs can greatly affect the output performance. The filter not only reduces
radiated EMI (snubber filter), but also filters high frequency content from the switching output before going
to the speaker (low-pass LC filter).
6.4.1
Half-Bridge Output Filter
Figure 25 shows the output filter for a half-bridge configuration. The transient-voltage suppression circuit
(snubber circuit) is comprised of a resistor (20 Ω, ¼ W) and capacitors (220 pF) and should be placed as
close as possible to the corresponding PWM output pin to greatly reduce radiated EMI.
C2
L1
OUTx
+
20 Ω
-
220 pF
C1
Figure 25. Output Filter - Half-Bridge
The inductor, L1, and capacitor, C1, comprise the low-pass filter. Along with the nominal load impedance
of the speaker, these values set the cutoff frequency of the filter. Table 15 shows the component values
for L1 and C1 based on nominal speaker (load) impedance for a corner frequency (-3 dB point) of approximately 35 kHz.
Load
L1
C1
4Ω
6Ω
8Ω
22 µH
33 µH
47 µH
1.0 µF
0.68 µF
0.47 µF
Table 15. Low-Pass Filter Components - Half-Bridge
C2 is the DC-blocking capacitor. Table 16 shows the component values for C2 based on corner frequency
(-3 dB point) and a nominal speaker (load) impedances of 4 Ω, 6 Ω, and 8 Ω. This capacitor should also
be chosen to have a ripple current rating above the amount of current that will passed 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 16. DC-Blocking Capacitors Values - Half-Bridge
54
DS726A1
CS4525
6.4.2
Full-Bridge Output Filter (Stereo or Parallel)
Figure 26 shows the output filter for a full-bridge configuration. The transient-voltage suppression circuit
(snubber circuit) is comprised of a resistor (20 Ω) and capacitor (330 pF) and should be placed as close
as possible to the corresponding PWM output pins to greatly reduce radiated EMI. The inductors, L1, and
capacitor, C1, comprise the low-pass filter. Along with the nominal load impedance of the speaker, these
values set the cutoff frequency of the filter. Table 17 shows the component values based on nominal
speaker (load) impedance for a corner frequency (-3 dB point) of approximately 35 kHz.
L1
OUT1
20 Ω
C1
330 pF
L1
OUT2
Figure 26. Output Filter - Full-Bridge
Load
L1
C1
4Ω
6Ω
8Ω
10 µH
15 µH
22 µH
1.0 µF
0.47 µF
0.47 µF
Table 17. Low-Pass Filter Components - Full-Bridge
DS726A1
55
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 27 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
365 Ω
AINL
1800 pF
C0G
100 kΩ
1 µF
Left Input
365 Ω
AINR
1800 pF
C0G
100 kΩ
Figure 27. Recommended Unity Gain Input Filter
To interface 2 VRMS input signals with the CS4525’s analog inputs, an external resistor divider is required.
Figure 28 shows the recommended input circuit for 2 VRMS inputs. It includes a -10.5 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
10 kΩ
4.32 kΩ
Right Input
10 kΩ
4.32 kΩ
1 µF
AINL
68 pF
C0G
1 µF
AINR
68 pF
C0G
Figure 28. 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.
56
DS726A1
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, 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.
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
I²S Mode, Data Valid on Rising Edge of SCLK
Bits/Sample
SCLK Rates
16
32, 48, 64, 128 Fs
18 to 24
48, 64, 128 Fs
Figure 29. 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
Left-Justified Mode, Data Valid on Rising Edge of SCLK
Bits/Sample
SCLK Rate(s)
16
32, 48, 64, 128 Fs
18 to 24
48, 64, 128 Fs
Figure 30. Left-Justified Serial Audio Formats
DS726A1
57
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. Either 16 bits per sample or 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
Right-Justified Mode, Data Valid on Rising Edge of SCLK
Bits/Sample
Supported SCLK Rate(s)
16
32, 48, 64, 128 Fs
24
48, 64, 128 Fs
Figure 31. Right-Justified Serial Audio Formats
58
DS726A1
CS4525
6.7
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 chip address. A pull-up
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 32 and Figure 25. 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 chip 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 chip 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
0
7
6
1
ACK
ACK
0
7
6
1
DATA +n
0
7
6
1
0
ACK
ACK
STOP
START
Figure 32. 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
STOP
MAP BYTE
0 1 AD0 0
INCR
6
5
4
3
2
1
ACK
CHIP ADDRESS (READ)
1
0
0
0
1
0
ACK
START
DATA
1 AD0 1
START
7
ACK
DATA +1
0
7
ACK
0
DATA + n
7
0
NO
ACK
STOP
Figure 33. 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 25, 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 (chip address & write operation).
Receive acknowledge bit.
Send MAP byte, auto increment off.
Receive acknowledge bit.
Send stop condition, aborting write.
Send start condition.
Send 100101x1(chip address & read operation).
DS726A1
59
CS4525
Receive acknowledge bit.
Receive byte, contents of selected register.
Send acknowledge bit.
Send stop condition.
Setting the auto increment bit in the MAP allows successive reads or writes of consecutive registers. Each
byte is separated by an acknowledge bit.
7. PCB LAYOUT CONSIDERATIONS
7.1
Power Supply, Grounding
As with any high-resolution converter, 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.
7.1.1
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 18 below.
LVD
Low
High
Indicated VD Supply Level
2.5 V or 3.3 V Nominal
5 V Nominal
Table 18. Input Source Selection
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 Specified 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.
7.2
QFN Thermal Pad
The CS4525 is available in a compact QFN package. 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.
60
DS726A1
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 64
1
0
0
1
0
0
0
EnAnHPF
Reserved
SPRate1
SPRate0
DIF2
DIF1
02h Input Config
ADC/SP
page 66
0
1
0
x
x
0
0
03h Aux Config
EnAuxPort DlyPortCfg1 DlyPortCfg0 AuxI²S/LJ RChDSel1 RChDSel0 LChDSel1
page 67
0
0
0
0
0
1
0
04h Output Cfg
OutputCfg1 OutputCfg0 PWMDSel1 PWMDSel0 OutputDly3 OutputDly2 OutputDly1
page 68
0
0
0
0
0
0
0
05h Foldback Cfg Reserved
EnTherm
LockAdj
AttackDly1 AttackDly0
EnFloor
RmpSpd1
page 69
0
0
0
0
1
0
1
06h Mixer Config PreScale2 PreScale1 PreScale0 Reserved
RChMix1
RChMix0
LChMix1
page 70
0
0
0
0
0
0
0
07h Tone Config
DeEmph
Loudness EnDigHPF
TrebFc1
TrebFc0
BassFc1
BassFc0
page 71
0
0
0
0
0
0
1
08h Tone Control
Treble3
Treble2
Treble1
Treble0
Bass3
Bass2
Bass1
page 72
1
0
0
0
1
0
0
09h EQ Config
Freeze
Reserved
BassMgr2 BassMgr1 BassMgr0 EnLFEPEq EnChBPEq
page 73
0
0
0
0
0
0
0
MSB
.............................................................................................................................
0Ah Channel 1&2
0Bh BiQuad 1
MSB-8
.............................................................................................................................
A1
Coeff
0Ch
LSB+7
.............................................................................................................................
MSB
.............................................................................................................................
0Dh Channel 1&2
0Eh BiQuad 1
MSB-8
.............................................................................................................................
0Fh A2 Coeff
LSB+7
.............................................................................................................................
MSB
.............................................................................................................................
10h Channel 1&2
11h BiQuad 1
MSB-8
.............................................................................................................................
12h B0 Coeff
LSB+7
.............................................................................................................................
13h Channel 1&2
MSB
.............................................................................................................................
14h BiQuad 1
MSB-8
.............................................................................................................................
B1
Coeff
15h
LSB+7
.............................................................................................................................
16h Channel 1&2
MSB
.............................................................................................................................
17h BiQuad 1
MSB-8
.............................................................................................................................
B2
Coeff
18h
LSB+7
.............................................................................................................................
19h Channel 1&2
MSB
.............................................................................................................................
1Ah BiQuad 2
MSB-8
.............................................................................................................................
1Bh A1 Coeff
LSB+7
.............................................................................................................................
1Ch Channel 1&2
MSB
.............................................................................................................................
1Dh BiQuad 2
MSB-8
.............................................................................................................................
1Eh A2 Coeff
LSB+7
.............................................................................................................................
1Fh Channel 1&2
MSB
.............................................................................................................................
20h BiQuad 2
MSB-8
.............................................................................................................................
21h B0 Coeff
LSB+7
.............................................................................................................................
22h Channel 1&2
MSB
.............................................................................................................................
23h BiQuad 2
MSB-8
.............................................................................................................................
B1
Coeff
24h
LSB+7
.............................................................................................................................
DS726A1
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
61
CS4525
Adr
Name
7
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
Channel 1&2
BiQuad 2
B2 Coeff
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
62
Channel 1&2
BiQuad 3
A1 Coeff
Channel 1&2
BiQuad 3
A2 Coeff
Channel 1&2
BiQuad 3
B0 Coeff
Channel 1&2
BiQuad 3
B1 Coeff
Channel 1&2
BiQuad 3
B2 Coeff
Channel 3
BiQuad 1
A1 Coeff
Channel 3
BiQuad 1
A2 Coeff
Channel 3
BiQuad 1
B0 Coeff
Channel 3
BiQuad 1
B1 Coeff
Channel 3
BiQuad 1
B2 Coeff
Channel 3
BiQuad 2
A1 Coeff
Channel 3
BiQuad 2
A2 Coeff
Channel 3
BiQuad 2
B0 Coeff
Channel 3
BiQuad 2
B1 Coeff
Channel 3
BiQuad 2
B2 Coeff
6
5
4
3
2
1
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
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
DS726A1
CS4525
Adr
Name
55h Volume Cfg
page 75
56h Sensitivity
page 76
57h Master Vol
page 77
58h Ch 1 Vol
page 78
59h Ch 2 Vol
page 78
5Ah Ch 3 Vol
page 78
5Bh Mute Control
page 78
5Ch Limiter Cfg 1
page 79
5Dh Limiter Cfg 2
page 80
5Eh Limiter Cfg 3
page 80
5Fh Power Ctrl
page 81
60h Interrupt
page 82
61h Int Status
page 84
62h Amp Error
page 85
63h Device ID
page 87
DS726A1
7
6
SZCMode1 SZCMode0
1
0
LowPass3 LowPass2
0
0
MVol7
MVol6
0
0
Ch1Vol7
Ch1Vol6
0
0
Ch2Vol7
Ch2Vol6
0
0
Ch3Vol7
Ch3Vol6
0
0
InvADC
InvCh3
0
0
Max2
Max1
0
0
Reserved
Reserved
0
0
Reserved
Reserved
0
0
Reserved
Reserved
0
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
Ch1Vol5
1
Ch2Vol5
1
Ch3Vol5
1
InvCh2
0
Max0
0
RRate5
1
ARate5
0
SelectVD
1
ChOvfl
x
Ch3OvflSt
x
OverCurr2
x
DeviceID2
0
AutoMute
1
LowPass0
0
MVol4
1
Ch1Vol4
1
Ch2Vol4
1
Ch3Vol4
1
InvCh1
0
Min2
0
RRate4
1
ARate4
0
PDnADC
1
AmpErr
x
Ch2OvflSt
x
OverCurr1
x
DeviceID1
0
3
2
1
0
En2Way 2WayFreq2 2WayFreq1 2WayFreq0
0
0
0
0
HighPass3 HighPass2 HighPass1 HighPass0
0
0
0
0
MVol3
MVol2
MVol1
MVol0
0
0
0
0
Ch1Vol3
Ch1Vol2
Ch1Vol1
Ch1Vol0
0
0
0
0
Ch2Vol3
Ch2Vol2
Ch2Vol1
Ch2Vol0
0
0
0
0
Ch3Vol3
Ch3Vol2
Ch3Vol1
Ch3Vol0
0
0
0
0
MuteADC
MuteCh3
MuteCh2
MuteCh1
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
UnderV
ThermErr ThermWarn
x
x
x
x
DeviceID0
RevID2
RevID1
RevID0
0
x
x
x
63
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
64
DS726A1
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 47 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 47
for more information.
FreqShift Setting
AM Frequency Shift State
0 ..........................................Frequency shift disabled.
1 ..........................................Frequency shift enabled.
DS726A1
65
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
Default = XX
Function:
Identifies the sample rate of the incoming LRCK signal on the serial audio input port.
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 57.
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.
66
DS726A1
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 42 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 57.
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 ........................................LFE Channel.
11.........................................Channel B crossover low-pass output.
DS726A1
67
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 ........................................ LFE Channel.
11......................................... Channel B crossover high-pass output.
9.4
Output Configuration Register (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 “PWM Power Output Configurations” on page 43 for more information.
OutputCfg[1:0] Setting
Power Output Configuration
00 ........................................ Channel 1 & 2 Full-Bridge.
01 ........................................ Channel 1 & 2 Half-Bridge + Channel 3 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 44 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.
Channel 3 output on PWM_SIG2.
11......................................... Channel 2 output on PWM_SIG1.
Channel 3 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
68
DS726A1
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 50 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
Reserved
9.5.1
6
EnTherm
5
LockAdj
4
AttackDly1
3
AttackDly0
2
EnFloor
1
RmpSpeed1
0
RmpSpeed0
Enable Thermal Foldback (EnTherm)
Default = 0
Function:
Enables the thermal foldback feature. See “Thermal Foldback” on page 39 for more information.
EnTherm Setting
Thermal Foldback State
0 ..........................................Disabled.
1 ..........................................Enabled.
9.5.2
Lock Foldback Adjust (LockAdj)
Default = 0
Function:
Controls the operation of the foldback lock adjustment feature. See “Thermal Foldback” on page 39 for
more information.
LockAdj Setting
Foldback Adjustment Lock State
0 ..........................................Attenuation lock disabled.
1 ..........................................Attenuation lock enabled.
9.5.3
Foldback Attack Delay (AttackDly[1:0])
Default = 01
Function:
Controls the foldback attack delay. See “Thermal Foldback” on page 39 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.
DS726A1
69
CS4525
9.5.4
Enable Foldback Floor (EnFloor)
Default = 0
Function:
Controls the foldback attenuation floor feature. See “Thermal Foldback” on page 39 for more information.
EnFloor Setting
Attenuation Floor
0 .......................................... No foldback attenuation floor imposed.
1 .......................................... Maximum foldback attenuation limited to -30 dB.
9.5.5
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 ........................................ Approximately 0.70 seconds.
01 ........................................ Approximately 0.75 seconds.
10 ........................................ Approximately 0.85 seconds.
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 29 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
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
70
DS726A1
CS4525
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.
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.
DS726A1
71
CS4525
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.
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 increments
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
72
DS726A1
CS4525
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 increments
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
Reserved
5
BassMgr2
4
BassMgr1
3
BassMgr0
2
EnLFEPEq
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 coefficients for
channel 1, channel 2 and channel 3 (address 0Ah - 54h) registers 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.
9.9.2
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
DS726A1
73
CS4525
9.9.3
Enable LFE Parametric EQ (EnLFEPEq)
Default = 0
Function:
Enables the parametric EQ 4 and 5 bi-quad filters for the LFE channel.
EnLFEPEq Setting
LFE Parametric EQ State
0 .......................................... Disabled.
1 .......................................... Enabled.
9.9.4
Enable Channel B Parametric EQ (EnChBPEq)
Default = 0
Function:
Enables the parametric EQ 1, 2, and 3 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 1, 2, and 3 bi-quad filters for channel A.
EnChAPEq Setting
Channel A Parametric EQ State
0 .......................................... Disabled.
1 .......................................... Enabled.
74
DS726A1
CS4525
9.10
Volume and 2-Way Cross-Over Configuration (Address 55h)
7
SZCMode1
9.10.1
6
SZCMode0
5
Mute50/50
4
AutoMute
3
En2Way
2
2WayFreq2
1
2WayFreq1
0
2WayFreq0
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:
Enables the outputs of the amplifiers to switch at an exact 50%-duty-cycle signal (not modulated) 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.
DS726A1
75
CS4525
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 1-2: 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 1 and Channel 2 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 41 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
76
DS726A1
CS4525
9.11.2
Channel 1 and Channel 2 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 41 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
9.12.1
6
MVol6
5
MVol5
4
MVol4
3
MVol3
2
MVol2
1
MVol1
0
MVol0
Master Volume Control (MVol[7:0])
Default = 30h
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
............................
0011 0000............................0.0 dB
0011 0001............................-0.5 dB
0011 0010............................-1.0 dB
............................
1111 1110.............................-103.0 dB
1111 1111 .............................Master Mute
DS726A1
77
CS4525
9.13
Channel 1, 2, & 3 Volume Control (Address 58h, 59h, & 5Ah)
7
ChXVol7
9.13.1
6
ChXVol6
5
ChXVol5
4
ChXVol4
3
ChXVol3
2
ChXVol2
1
ChXVol1
0
ChXVol0
Channel X Volume Control (ChXVol[7:0])
Default = 30h
Function:
Sets the gain/attenuation levels of the channel 1, 2, and 3 individual volume controls. 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
Mute/Invert Control (Address 5Bh)
7
InvADC
9.14.1
6
InvCh3
5
InvCh2
4
InvCh1
3
MuteADC
2
MuteCh3
1
MuteCh2
0
MuteCh1
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.
9.14.2
Invert Signal Polarity (InvChX)
Default = 0
Function:
When set, the signal polarity of the respective channels will be inverted.
InvChX Setting
Channel X Signal Inversion State
0 .......................................... Channel X signal polarity not inverted.
1 .......................................... Channel X signal polarity inverted.
9.14.3
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.
78
DS726A1
CS4525
9.14.4
Independent Channel Mute (MuteChX)
Default = 0
Function:
The PWM outputs of the CS4525 will mute 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.
MuteChX Setting
Channel X Mute State
0 ..........................................Channel X un-muted.
1 ..........................................Channel X muted.
9.15
Limiter Configuration 1 (Address 5Ch)
7
Max2
9.15.1
6
Max1
5
Max0
4
Min2
3
Min1
2
Min0
1
LimitAll
0
EnLimiter
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
9.15.2
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
9.15.3
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
DS726A1
79
CS4525
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.
9.15.4
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.
9.16
Limiter Configuration 2 (Address 5Dh)
7
Reserved
9.16.1
6
Reserved
5
RRate5
4
RRate4
3
RRate3
2
RRate2
1
RRate1
0
RRate0
Limiter Release Rate (RRate[5:0])
Default = 000000
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
00000 .................................. Fastest release.
...................................
11111.................................... Slowest release.
9.17
Limiter Configuration 3 (Address 5Eh)
7
Reserved
9.17.1
6
Reserved
5
ARate5
4
ARate4
3
ARate3
2
ARate2
1
ARate1
0
ARate0
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.
80
DS726A1
CS4525
9.18
Power Control (Address 5Fh)
7
Reserved
9.18.1
6
Reserved
5
SelectVD
4
PDnADC
3
PDnOut3/4
2
PDnOut2
1
PDnOut1
0
PDnAll
Select VD Level (SelectVD)
Default = 1
Function:
This bit selects between a VD of 2.5 V or 3.3 V when the LVD pin is connected to DGND. This bit is ignored
when the LVD pin is connected to VD.
SelectVD Setting
Selected VD Level
0 ..........................................VD = 2.5 V.
1 ..........................................VD = 3.3 V.
9.18.2
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.
9.18.3
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.
9.18.4
Power Down (PDnAll)
Default = 1
Function:
The entire device will enter a low-power state when this function is enabled, and the contents of the control
registers are retained in this mode. The power-down 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.
DS726A1
81
CS4525
9.19
Interrupt Register (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 “edgetrigger” 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.
9.19.1
SRC Lock State Transition Interrupt Bit (SRCLock)
Default = 0
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.
9.19.2
ADC Overflow Interrupt Bit (ADCOvfl)
Default = 0
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.
9.19.3
Channel Overflow Interrupt Bit (ChOvfl)
Default = 0
Function:
This bit is read only. When set, indicates that the magnitude of an output sample on channel 1, 2, or 3 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.
82
DS726A1
CS4525
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 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.
9.19.4
Amplifier Error Interrupt Bit (AmpErr)
Default = 0
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.
9.19.5
Mask Bit 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.
9.19.6
Mask Bit 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.
DS726A1
83
CS4525
9.19.7
Mask Bit for Channel X Overflow (ChOvflM)
Default = 0
Function:
This bit serves as a mask for the channel 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 and ChXOvflSt 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.
9.19.8
Mask Bit 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.
9.20
Interrupt Status Register (Address 61h) - Read Only
7
SRCLockSt
6
ADCOvflSt
5
Ch3OvflSt
4
Ch2OvflSt
3
Ch1OvflSt
2
RampDone
1
Reserved
0
Reserved
All bits in this register are considered “level-trigger” 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.
9.20.1
SRC State Transition (SRCLockSt)
Default = 0
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.
84
DS726A1
CS4525
9.20.2
ADC Overflow (ADCOvfl)
Default = 0
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.
ADCOvfl Setting
ADC Overflow State
0 ..........................................An ADC overflow condition is not currently present.
1 ..........................................An ADC overflow condition is currently present.
9.20.3
Channel X Overflow (ChXOvfl)
Default = 0
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.
ChXOvfl 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.
9.20.4
Ramp-Up Cycle Complete (RampDone)
Default = 0
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.
9.21
Amplifier Error Status (Address 62h) - Read Only
7
OverCurr4
6
OverCurr3
5
OverCurr2
4
OverCurr1
3
ExtAmpErr
2
UnderV
1
ThermErr
0
ThermWarn
All bits in this register are considered “level-trigger” 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
Over-Current Detected On Channel X (OverCurrX)
Default = 0
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.
DS726A1
85
CS4525
9.21.2
External Amplifier State (ExtAmpSt)
Default = 0
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.
9.21.3
Under Voltage Detected (UnderV)
Default = 0
Function:
When set, indicates an undervoltage condition is currently present on the VP voltage rail.
UnderV Setting
VP Under Voltage Status
0 .......................................... An under-voltage condition is not currently present on the VP supply.
1 .......................................... An under-voltage condition is currently present on the VP supply.
9.21.4
Thermal Error Detected (ThermErr)
Default = 0
Function:
When set, indicates a thermal error condition (specified by the thermal error trip point listed in the PWM
Power Output Characteristics table on page 20) is currently present.
ThermErr Setting
Thermal Error Status
0 .......................................... A thermal error condition is not currently present.
1 .......................................... A thermal error condition is currently present.
9.21.5
Thermal Warning Detected (ThermWarn)
Default = 0
Function:
When set, indicates a thermal warning condition (specified by the thermal warning trip point listed in the
PWM Power Output Characteristics table on page 20) is currently present.
ThermWarn Setting
Thermal Warning Status
0 .......................................... A thermal warning condition is not currently present.
1 .......................................... A thermal warning condition is currently present.
86
DS726A1
CS4525
9.22
Chip I.D. and Revision Register (Address 63h) - Read Only
7
DeviceID4
9.22.1
6
DeviceID3
5
DeviceID2
4
DeviceID1
3
DeviceID0
2
RevID2
1
RevID1
0
RevID0
Device Identification (DeviceID[4:0])
Default =11000
Function:
Identification code for the CS4525.
DeviceID[4:0] Setting
Device ID Notes
11000...................................Permanent device identification code.
9.22.2
Device Revision (RevID[2:0])
Default = 000
Function:
CS4525 revision level.
RevID[2:0] Setting
Device Revision ID
000 ......................................Revision A0.
DS726A1
87
CS4525
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
at -1 and -20 dBFS 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
88
DS726A1
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
6.95
6.95
0.70
1
1
1,2
1
1
1
1
1
1
JEDEC #: MO-220
Controlling Dimension is Millimeters.
Table 19:
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.
DS726A1
89
CS4525
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 0.15*PRMS (assuming 85% efficiency)
θJC = Junction-to-case thermal resistance of the device in °C/Watt
14.ORDERING INFORMATION
90
Product
Description
Package
Pb-Free
Grade
Temp Range Container
Digital TV Amp with
Integrated ADC
Rail
CS4525-CNZ
CS4525
48-QFN
Yes
Commercial
-10° to +70°C
Tape and
Reel
CS4525-CNZR
CRD4525
2 x 15 W
Reference Design
Board
-
-
-
-
-
CRD4525
CRD4412
1 x 30 W
Reference Design
Daughter Card
-
-
-
-
-
CRD4412
Order#
DS726A1
CS4525
15.REVISION HISTORY
Release
A1
Changes
Initial Release
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
“Advance” product information describes products that are in development and subject to development changes. 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 AIRCRAFT SYSTEMS, MILITARY APPLICATIONS, 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.
DS726A1
91
Similar pages