CS4234 - Cirrus Logic

CS4234
4 In/5 Out CODEC with Programmable Class H Controller
DAC Features
System Features
 Advanced multibit Delta–Sigma modulator
 TDM, left justified, and I2S serial inputs and outputs
 24-bit resolution
 Nondelayed low-latency path
 Differential or single-ended outputs
 Supports sample rates up to 96 kHz
 -109 dB dynamic range (A-weighted)
Class H Controller Features
 -90 dB THD+N
 Can be used with any integrated Class AB amplifier
IC or discrete amplifier solution.
 2 Vrms full-scale output into 3-k AC load
 Rail-to-rail operation
 Increases efficiency of Class AB amplifiers
 Programmable group delay in 4-channel audio
output path
 Creates audio tracking reference signal for external
switch-mode power supply
ADC Features
 Internal envelope tracking of up to 32 channels
 Input path for externally generated tracking signal
 Advanced multibit Delta–Sigma modulator
 24-bit resolution
Common Applications
 Differential inputs
 Discrete Class H automotive audio amplifiers
 -105 dB dynamic range (A-weighted)
 - 88 dB THD+N
 Automotive head units with internal Class H
amplifiers
 2 Vrms full-scale input
 Audio mixing consoles
 Audio effects processors
VD
2.5 VDC
VA
5.0 VDC
-1 -2
2.5 V
Gain / Volume
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert ,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elect
Mode
Select
DC Offset
X

Full Scale Code
Master Volume
0 dB
Filter
Select
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
(±)
(±)
(±)
(±)
5 th DAC
Input Advisory
Multi-bit
 ADC
Group
Delay
0-500uS
Digital Filters
Low -Latency
Demux
Channel Volume ,
Mute, Invert,
Noise Gate
Master
Volume
Control
Mute, Invert,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Control )
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
Serial Audio Interface
Control Port
Level Translator
SDOUTx
SDIN 2
SDIN1
Frame Sync
Clock / LRCK
Master Clock In
Serial Clock
In / Out
VL
1.8 to 5.0 VDC
http://www.cirrus.com
Copyright  Cirrus Logic, Inc. 2012
(All Rights Reserved)
INT
RST
I2C Control
Data
MAR ‘12
DS899F1
CS4234
General Description
The CS4234 is a highly versatile CODEC that combines 4 channels of high performance analog to digital conversion, 4 channels of high performance digital to analog conversion for audio, and 1 channel of digital to analog
conversion to provide a nondelayed audio reference signal to an external Class H tracking power supply. If not used
to drive a tracking power supply, the 5th DAC can instead be used as a standard audio grade DAC, with performance
specifications identical to that of the 4 DACs in the audio path. Additionally, the CS4234 includes tunable group delay for each of the 4 audio DAC paths to provide lead time for the external switch-mode power supply, and a
nondelayed path into the DAC outputs for input signals requiring a low-latency path to the outputs.
Targeting the automotive audio market, this controller was specifically designed to work with Apex Precision Power’s
CS44417 Class AB audio amplifier, but remains flexible enough to allow any standard Class AB amplifier to be operated as a Class H amplifier in order to maximize efficiency. Class H control provides significant efficiency gains
over traditional Class AB amplifiers, while avoiding the increased electromagnetic interference (EMI) and cost of
Class D amplifiers.
The Class H controller provides a reference signal which tracks the envelope of the maximum (on a sample by sample basis) of up to 32 channels of serial data in the TDM slots input on the SDINx lines. This reference signal is sent
to the 5th DAC to create an analog reference signal for an external switch-mode power supply that supplies rail voltages to an external Class AB amplifier, thereby turning any standard Class AB amplifier into a Class H amplifier. If
desired, the internal tracking power supply circuitry can be bypassed, which allows a DSP generated tracking signal
to be used to control the SMPS. This feature allows an unlimited number of channels to be tracked, using a DSP to
create the tracking signal.
This product is available in a 40-pin QFN package in Automotive (-40 °C to +105 °C) temperature grade. See “Ordering Information” on page 74 for complete details.
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CS4234
TABLE OF CONTENTS
1. PIN DESCRIPTIONS ............................................................................................................................ 6
1.1 I/O Pin Characteristics ..................................................................................................................... 7
2. TYPICAL CONNECTION DIAGRAM ................................................................................................... 8
3. CHARACTERISTICS AND SPECIFICATIONS ...................................................................................... 9
RECOMMENDED OPERATING CONDITIONS .................................................................................... 9
ABSOLUTE MAXIMUM RATINGS ........................................................................................................ 9
DC ELECTRICAL CHARACTERISTICS .............................................................................................. 10
TYPICAL CURRENT CONSUMPTION ............................................................................................... 11
ANALOG INPUT CHARACTERISTICS .............................................................................................. 12
ADC DIGITAL FILTER CHARACTERISTICS ...................................................................................... 14
ANALOG OUTPUT CHARACTERISTICS ........................................................................................... 15
COMBINED DAC INTERPOLATION AND ON-CHIP ANALOG FILTER RESPONSE ........................ 16
DIGITAL I/O CHARACTERISTICS ...................................................................................................... 17
SWITCHING CHARACTERISTICS - SERIAL AUDIO INTERFACE .................................................... 18
SWITCHING SPECIFICATIONS - CONTROL PORT .......................................................................... 20
4. APPLICATIONS ................................................................................................................................... 21
4.1 Power Supply Decoupling, Grounding, and PCB Layout ............................................................... 21
4.2 Recommended Power-Up and Power-Down Sequence ................................................................ 21
4.3 I²C Control Port .............................................................................................................................. 25
4.4 System Clocking ............................................................................................................................ 26
4.5 Serial Port Interface ....................................................................................................................... 28
4.6 Internal Signal Path ....................................................................................................................... 32
4.7 Reset Line ...................................................................................................................................... 47
4.8 Error Reporting and Interrupt Behavior .......................................................................................... 47
5. REGISTER QUICK REFERENCE ........................................................................................................ 50
6. REGISTER DESCRIPTIONS ................................................................................................................ 52
6.1 Device I.D. A and B (Address 01h) (Read Only)
Device I.D. C and D (Address 02h) (Read Only)
Device I.D. E and F (Address 03h) (Read Only) ............................................................................... 52
6.2 Revision I.D. (Address 05h) (Read Only) ....................................................................................... 52
6.3 Clock and SP Select (Address 06h) ............................................................................................... 53
6.4 Sample Width Select (Address 07h) .............................................................................................. 54
6.5 Serial Port Control (Address 08h) .................................................................................................. 55
6.6 Serial Port Data Select (Address 09h) ........................................................................................... 56
6.7 Serial Data Input 1 Mask 1 (Address 0Ah) ..................................................................................... 57
6.8 Serial Data Input 1 Mask 2 (Address 0Bh) ..................................................................................... 57
6.9 Serial Data Input 2 Mask 1 (Address 0Ch) .................................................................................... 58
6.10 Serial Data Input 2 Mask 2 (Address 0Dh) .................................................................................. 58
6.11 Tracking Power Supply Control (Address 0Eh) ........................................................................... 59
6.12 ADC Control 1 (Address 0Fh) ...................................................................................................... 60
6.13 ADC Control 2 (Address 10h) ...................................................................................................... 61
6.14 Low Latency Path Control (Address 11h) .................................................................................... 61
6.15 DAC Control 1 (Address 12h) ...................................................................................................... 62
6.16 DAC Control 2 (Address 13h) ...................................................................................................... 63
6.17 DAC Control 3 (Address 14h) ...................................................................................................... 63
6.18 DAC Control 4 (Address 15h) ...................................................................................................... 64
6.19 Volume Mode (Address 16h) ....................................................................................................... 65
6.20 Master and DAC1-5 Volume Control (Address 17h, 18h, 19h, 1Ah, 1Bh, and 1Ch) ................... 66
6.21 Interrupt Control (Address 1Eh) ................................................................................................... 66
6.22 Interrupt Mask 1 (Address 1Fh) ................................................................................................... 67
6.23 Interrupt Mask 2 (Address 20h) ................................................................................................... 68
6.24 Interrupt Notification 1 (Address 21h) (Read Only) ...................................................................... 68
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CS4234
6.25 Interrupt Notification 2 (Address 22h) (Read Only) ...................................................................... 69
7. ADC FILTER PLOTS ............................................................................................................................ 70
8. DAC FILTER PLOTS ............................................................................................................................ 71
9. PACKAGE DIMENSIONS ................................................................................................................... 73
10. ORDERING INFORMATION .............................................................................................................. 74
11. APPENDIX A:INTERNAL TRACKING POWER SUPPLY SIGNAL .................................................. 74
11.1 Voltage Headroom ....................................................................................................................... 76
11.2 Lead Time .................................................................................................................................... 76
11.3 Gain Matching .............................................................................................................................. 76
11.4 SMPS (TPS) Modes ..................................................................................................................... 77
12. REVISION HISTORY .......................................................................................................................... 79
LIST OF FIGURES
Figure 1. CS4234 Pinout ............................................................................................................................. 6
Figure 2. Typical Connection Diagram ........................................................................................................ 8
Figure 3. Test Circuit for ADC Performance Testing ................................................................................. 13
Figure 4. PSRR Test Configuration ........................................................................................................... 13
Figure 5. Equivalent Output Test Load ..................................................................................................... 15
Figure 6. TDM Serial Audio Interface Timing ............................................................................................ 19
Figure 7. PCM Serial Audio Interface Timing ............................................................................................ 19
Figure 8. I²C Control Port Timing .............................................................................................................. 20
Figure 9. System Level Initialization and Power-up / Power-down Sequence .......................................... 23
Figure 10. DAC DC Loading ..................................................................................................................... 24
Figure 11. Timing, I²C Write ...................................................................................................................... 25
Figure 12. Timing, I²C Read ...................................................................................................................... 25
Figure 13. Master Mode Clocking ............................................................................................................. 27
Figure 14. TDM System Clock Format ...................................................................................................... 28
Figure 15. 32-bit Receiver Channel Block ................................................................................................. 29
Figure 16. Serial Data Coding and Extraction Options within the TDM Streams ...................................... 30
Figure 17. Left Justified Format ................................................................................................................ 31
Figure 18. I²S Format ................................................................................................................................ 31
Figure 19. Audio Path Routing .................................................................................................................. 32
Figure 20. Conventional SDOUT1 (Left) vs. Sidechain SDOUT1 (Right) Configuration ........................... 33
Figure 21. DAC1-4, Low Latency, and DAC5 Path Serial Data Source Selection .................................... 34
Figure 22. Example Serial Data Source Selection .................................................................................... 35
Figure 23. ADC Path ................................................................................................................................. 38
Figure 24. DAC1-4 Path ............................................................................................................................ 39
Figure 25. De-emphasis Curve ................................................................................................................. 40
Figure 26. Low-latency Path ..................................................................................................................... 40
Figure 27. DAC5 Path ............................................................................................................................... 41
Figure 28. Volume Implementation for the DAC1-4 and Low-latency Path ............................................... 43
Figure 29. Volume Implementation for the DAC5 Path ............................................................................. 43
Figure 30. Soft Ramp Behavior ................................................................................................................. 45
Figure 31. Interrupt Behavior and Example Interrupt Service Routine ...................................................... 49
Figure 32. ADC Stopband Rejection ......................................................................................................... 70
Figure 33. ADC Transition Band ............................................................................................................... 70
Figure 34. ADC Transition Band (Detail) ................................................................................................... 70
Figure 35. ADC Passband Ripple ............................................................................................................. 70
Figure 36. ADC HPF (48 kHz) ................................................................................................................... 70
Figure 37. ADC HPF (96 kHz) ................................................................................................................... 70
Figure 38. SSM DAC Stopband Rejection ................................................................................................ 71
Figure 39. SSM DAC Transition Band ...................................................................................................... 71
Figure 40. SSM DAC Transition Band (Detail) .......................................................................................... 71
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CS4234
Figure 41. SSM DAC Passband Ripple .................................................................................................... 71
Figure 42. DSM DAC Stopband Rejection ................................................................................................ 72
Figure 43. DSM DAC Transition Band ...................................................................................................... 72
Figure 44. DSM DAC Transition Band (Detail) .......................................................................................... 72
Figure 45. DSM DAC Passband Ripple .................................................................................................... 72
Figure 46. Package Drawing ..................................................................................................................... 73
Figure 47. Progression of the Tracking Signal Through the DAC5 Path ................................................... 75
Figure 48. Directly Proportional vs. Indirectly Proportional Modes of Operation ....................................... 77
Figure 49. DAC5 TPS Modes of Operation ............................................................................................... 78
Figure 50. DAC5 Volume and TPS Offset Controls .................................................................................. 78
LIST OF TABLES
Table 1. Speed Modes .............................................................................................................................. 26
Table 2. Common Clock Frequencies ....................................................................................................... 27
Table 3. Master Mode Left Justified and I²S Clock Ratios ........................................................................ 27
Table 4. Slave Mode Left Justified and I²S Clock Ratios .......................................................................... 28
Table 5. Slave Mode TDM Clock Ratios ................................................................................................... 28
Table 6. Unmasking SDIN1 Data from DAC5 Path ................................................................................... 36
Table 7. Unmasking SDIN2 Data from DAC5 Path ................................................................................... 37
Table 8. Soft Ramp Rates ......................................................................................................................... 46
Table 9. Noise Gate Bit Depth Settings .................................................................................................... 46
Table 10. Error Reporting and Interrupt Behavior Details ......................................................................... 47
DS899F1
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CS4234
SCL
AD0
AD1
AD2/SDOUT2
INT
RST
AOUT5+
AOUT5-
AOUT1+
AOUT1-
40
39
38
37
36
35
34
33
32
31
1. PIN DESCRIPTIONS
SDA
1
30
AOUT2+
SDIN1
2
29
AOUT2-
SDIN2
3
28
AOUT3+
FS/LRCK
4
27
AOUT3-
MCLK
5
26
AOUT4+
SCLK
6
25
AOUT4-
SDOUT1
7
24
VBIAS
Top-Down
(Though Package)
View
18
19
20
AIN1-
FILT+
VA
16
AIN2-
17
15
AIN2+
AIN1+
14
GND
AIN3-
21
13
10
AIN3+
VQ
VDREG
12
VREF
22
AIN4-
23
9
11
8
AIN4+
VL
GND
Figure 1. CS4234 Pinout
Pin Name
SDA
SDINx
Pin #
1
2,3
Pin Description
Serial Control Data (Input/Output) - Bidirectional data I/O for the I²CTM control port.
Serial Data Input (Input) - Input channels serial audio and low latency data.
FS/LRCK
4
Frame Synchronization Clock/Left/Right Clock (Input/Output) - Determines which channel or
frame is currently active on the serial audio data line.
MCLK
5
Master Clock (Input) -Clock source for the internal logic, processing, and modulators.
SCLK
6
Serial Clock (Input/Output) -Serial Clock for the serial data port.
SDOUT1
7
Serial Data Output 1 (Output) - ADC data output into a multi-slot TDM stream or AIN1 and AIN2
ADC data output in Left Justified and I²S modes.
VL
8
Interface Power (Input) - Positive power for the digital interface level shifters.
GND
VDREG
9,21
10
Ground (Input) - Ground reference for the I/O and digital, analog sections.
Digital Power (Output) - Internally generated positive power supply for digital section.
AINx+
11,13,15, Positive Analog Input (Input) - Positive input signals to the internal analog to digital converters.
17
The full scale analog input level is specified in the Analog Input Characteristics table.
AINx-
12,14,16, Negative Analog Input (Input) - Negative input signals to the internal analog to digital converters.
18
The full scale analog input level is specified in the Analog Input Characteristics table.
FILT+
19
Positive Voltage Reference (Output) - Positive reference voltage for the internal ADCs.
VA
20
Analog Power (Input) - Positive power for the analog sections.
VQ
22
Quiescent Voltage (Output) - Filter connection for internal quiescent voltage.
VREF
23
Analog Power Reference (Input) - Return pin for the VBIAS cap.
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CS4234
Pin Name
Pin #
VBIAS
24
Pin Description
Positive Voltage Reference (Output) - Positive reference voltage for the internal DACs.
AOUTx-
25,27,29, Negative Analog Output (Output) - Negative output signals from the internal digital to analog con31, 33 verters. The full scale analog output level is specified in the Analog Output Characteristics table.
AOUTx+
26,28,30, Positive Analog Output (Output) - Positive output signals from the internal digital to analog con32, 34 verters. The full scale analog output level is specified in the Analog Output Characteristics table.
RST
35
Reset (Input) - Applies reset to the internal circuitry when pulled low.
INT
36
Interrupt (Output) - Sent to DSP to indicate an interrupt condition occurred.
AD2/SDOUT2
37
I²C Address Bit 2/Serial Data Output 2 (Input/Output) - Sets the I²C address bit 2 at reset. Functions as Serial Data Out 2 for AIN3 and AIN4 ADC data output in Left Justified and I²S modes. High
impedance in TDM mode. See Section 4.3 I²C Control Port for more details concerning this mode of
operation.
AD1
38
I²C Address Bit 1 (Input) - Sets the I²C address bit 1.
AD0
39
I²C Address Bit 0 (Input) - Sets the I²C address bit 0.
SCL
40
Serial Control Port Clock (Input) - Serial clock for the I²C control port.
GND
-
1.1
Thermal Pad - The thermal pad on the bottom of the device should be connected to the ground
plane via an array of vias.
I/O Pin Characteristics
Input and output levels and associated power supply voltage are shown in the table below. Logic levels
should not exceed the corresponding power supply voltage.
Power Supply
VL
Pin Name
I/O
Driver
SCL
Input
SDA
Input/Output
INT
Output
CMOS/Open
Drain
CMOS/Open
Drain
5.0 V CMOS5.0 V CMOS5.0 V CMOS
5.0 V CMOS-
Input
RST
MCLK
Input
FS/LRCK
Input/Output
SCLK
Input/Output
SDOUT1
Output
SDINx
Input
AD0,1
Input
AD2/SDOUT2 Input/Output
Internal Connections
Receiver
(Note 1)
Weak Pull-down (~500k 5.0 V CMOS, with Hysteresis
Weak Pull-down (~500k 5.0 V CMOS, with Hysteresis
(Note 2)
-
(Note 2)
Weak Pull-down (~500k
Weak Pull-down (~500k
Weak Pull-down (~500k
Weak Pull-down (~500k
Weak Pull-down (~500k
(Note 2)
(Note 2)
5.0 V CMOS, with Hysteresis
5.0 V CMOS, with Hysteresis
5.0 V CMOS, with Hysteresis
5.0 V CMOS, with Hysteresis
5.0 V CMOS, with Hysteresis
5.0 V CMOS
5.0 V CMOS
Notes:
1. Internal connection valid when device is in reset.
2. This pin has no internal pull-up or pull-down resistors. External pull-up or pull-down resistors should
be added in accordance with Figure 2.
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0.1 uF
5.0 VD C
0 .1u F
1 0u F
S CL K
S DO UT1
6
7
10
9
V DR EG
GN D
RT
13
C S4234
12
M C LK
5
11
FS/ LR C K
4
VL
S DI N2
3
8
S DI N1
40
SCL
AIN 4+
2
39
AD 0
AIN 4-
S DA
37
38
AD 1
AIN 3+
1
32
33
34
35
36
INT
AD 2
Pull Up or Down
B as ed upon
Desired A ddress .
RST
AIN 3-
RT
14
AIN 2+
15
AIN 2-
RT
16
17
RT
18
1 uF
19
AIN 1+
Digital Signal
Proc essor
3 k(x5 )
AOUT5-
AOUT5+
AIN 1-
31
29
28
27
26
25
24
23
22
21
AO UT2 AO UT3 +
AO UT3 AO UT4 +
AO UT4 VB IAS
VR E F
VQ
GN D
R REF
0. 1uF
20
10 uF
5.0 VD C
30
AO UT2 +
AOUT1-
5. 0 V DC
AOUT1+
FILT +
DS899F1
VA
1 0u F
0 .1 uF
1 0u F
22 uF
22 uF
22 uF
22 uF
22 uF
22 uF
22 uF
22 uF
10 uF
40 k
0 .1 uF
5.0 VD C
10 uF
VP-
44
43
A D1
2
AD0
42
AD 2/S D OU T2
A IN 4+
A IN 4-
3
1
41
OU T4+
I MO N4
4
40
39
38
VPOU T4-
37
36
35
34
33
32
31
30
OU T3+
VP+
OU T3-
VP-
VP-
OU T2 +
V P+
29
VP+
(H ea t S lu g)
V POU T2 -
28
27
I MO N3
A IN 3-
A IN 3+
I RE F
M U TE
S TBY
G ND
VA
A IN 2-
A IN 2+
V P+
OU T1 +
5
6
7
8
9
10
11
12
13
14
I MO N2
I MO N1
16
15
A IN 1-
A IN 1+
17
18
26
25
OU T1 -
D IA G_R A MP
I NT
RS T
19
20
23
24
V PVL
C S44417
SDA
SCL
(Inc ludes SMPS Controller with PWM
Modulator, Gate Drive(s), Power
Devices, Magnetics )
Switc h-Mode Power Supply
21
22
VB ATT
C2 C 2
C2 C 2
C1
C1
0. 1uF
5 .0 VD C
C2 C2
C2 C2
C1
C1
B ulk & Bypa ss C ap acito rs
C 1: 0.1 uF C e ra mic X 7R
C 2 : 4 7u F Electro lyt ic
P ull Up or Down
B ase d upon
Desi red A ddres s.
C1
C1
C1
C1
3 .3 u F
-VP
+V P
CS4234
2. TYPICAL CONNECTION DIAGRAM
Figure 2. Typical Connection Diagram
8
CS4234
3. CHARACTERISTICS AND SPECIFICATIONS
RECOMMENDED OPERATING CONDITIONS
GND = 0 V; all voltages with respect to ground. (Note 3)
Parameters
Symbol
Min
Typ
Max
Units
Analog Core
VA
3.135
4.75
3.3
5
3.465
5.25
V
V
Level Translator
VL
1.71
-
5.25
V
Ambient Operating Temperature - Power Applied
TA
-40
-
+105
C
Junction Temperature
TJ
-40
-
+150
C
DC Power Supply
Temperature
Notes:
3. Device functional operation is guaranteed within these limits. Functionality is not guaranteed or
implied outside of these limits. Operation outside of these limits may adversely affect device reliability.
ABSOLUTE MAXIMUM RATINGS
GND = 0 V; all voltages with respect to ground.
Parameters
Symbol
Min
Max
Units
Analog Core
VA
-0.3
5.5
V
Level Translator
VL
-0.3
5.5
V
(Note 4)
IVDREG
-
10
A
Input Current
(Note 5)
Iin
-
±10
mA
Analog Input Voltage
(Note 6)
VINA
- 0.3
VA + 0.4
V
Logic Level Input Voltage
(Note 6)
VIND
-0.3
VL + 0.4
V
Ambient Operating Temperature - Power Applied
TA
-55
+125
°C
Storage Temperature
Tstg
-65
+150
°C
DC Power Supply
VDREG Current
Inputs
Temperature
WARNING: OPERATION BEYOND THESE LIMITS MAY RESULT IN PERMANENT DAMAGE TO THE DEVICE.
Notes:
4. No external loads should be connected to the VDREG pin. Any connection of a load to this point may
result in errant operation or performance degradation in the device.
5. Any pin except supplies. Transient currents of up to ±100 mA on the analog input pins will not cause
SCR latch-up.
6. The maximum over/under voltage is limited by the input current.
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CS4234
DC ELECTRICAL CHARACTERISTICS
GND = 0 V; all voltages with respect to ground.
Parameters
Min
Typ
Max
Units
-
2.5
0.5
-
V

-
VA
23
-
1
V
k
A
-
0.5•VA
77
-
0
V
k
A
VDREG (Note 7)
Nominal Voltage
Output Impedance
FILT+
Nominal Voltage
Output Impedance
DC Current Source/Sink
VQ
Nominal Voltage
Output Impedance
DC Current Source/Sink
Notes:
7. No external loads should be connected to the VDREG pin. Any connection of a load to this point may
result in errant operation or performance degradation in the device.
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CS4234
TYPICAL CURRENT CONSUMPTION
This table represents the power consumption for individual circuit blocks within the CS4234. CS4234 is configured as
shown in Figure 2 on page 8. VA_SEL = 0 for VA = 3.3 VDC, 1 for VA = 5.0 VDC; FS = 100 kHz; MCLK = 25.6 MHz;
DAC load is 3 k; All input signals are zero (digital zero for SDINx inputs and AC coupled to ground for AINx
inputs) .
Typical Current [mA]
(unless otherwise noted)
(Note 9), (Note 12)
Functional Block
Reset Overhead
1 (All lines held static, RST line pulled low.)
Power Down Overhead
2 (All lines clocks and data lines active, RST line pulled high, All PDNx bits set high.)
PLL(Note 10)
3 (Current drawn resulting from PLL being active. PLL is active for 256x and 384x)
DAC Overhead
4 (Current drawn whenever any of the five DACs are powered up.)
DAC Channel (Note 8)
5 (Current drawn per each DAC powered up.)
ADC Overhead
6 (Current drawn whenever any of the four ADCs are powered up.)
ADC Group
7 (Current drawn due to an ADC “group” being powered up. See (Note 11))
ADC Channel
8 (Current drawn per each ADC powered up.)
VA/VL
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
iVA
iVL
0.030
0.020
5
5
1
1
50
45
5
4
11
11
2
2
2
2
0.001
0.001
0.101
0.101
0.109
0.066
Notes:
8. Full-scale differential output signal.
9. Current consumption increases with increasing FS and increasing MCLK. Values are based on FS of
100 kHz and MCLK of 25.6 MHz. Current variance between speed modes is small.
10. PLL is activated by setting the MCLK RATE bit to either 000 (operating in 256x mode) or 001 (operating
in 384 kHz).
11. Internal to the CS4234, the analog to digital converters are grouped together in stereo pairs. ADC1 and
ADC2 are grouped together as are ADC3 and ADC4. The ADC group current draw is the current that
is drawn whenever one of these groups become active.
12. To calculate total current draw for an arbitrary amount of ADCs or DACs, the following equations apply:
Total Running Current Draw from VA Supply = Power Down Overhead + PLL (If Applicable)+ DAC Current Draw + ADC Current Draw
where
DAC Current Draw = DAC Overhead + (Number of DACs x DAC Channel)
ADC Current Draw = ADC Overhead + (Number of active ADC Groups x ADC Group) + (Number of active ADC Channels x ADC Channel)
and
Total Running Current Draw from VL Supply = PDN Overhead + (Number of active ADC Channels x ADC Channel)
DS899F1
11
CS4234
ANALOG INPUT CHARACTERISTICS
Test Conditions (unless otherwise specified): Device configured as shown in Figure 2 on page 8. Input sine wave:
1 kHz; VA_SEL = 0 for VA = 3.3 VDC, 1 for VA = 5.0 VDC.; TA = -40 to +105 C; Measurement Bandwidth is 20 Hz
to 20 kHz unless otherwise specified; Sample Rate = 48 kHz; all Power Down ADCx bits = 0.
VA, VREF = 3.3 V
Parameter
Min
VA, VREF = 5.0 V
Typ
Max
Min
Typ
Max
Unit
101
98
-
97
94
105
102
-
dB
dB
-95
-38
-87
-30
-
-88
-42
-80
-34
dB
dB
0.2
±100
-
-
0.2
±100
-
ppm/°C
0.0001
0.25
90
-
-
0.0001
0.25
90
-
% Full Scale
% Full Scale
dB
1.66•VA
40
60
1.74•VA
-
45
20
-
Dynamic Range
A-weighted
93
unweighted
90
Total Harmonic Distortion + Noise
-1 dBFS
-60 dBFS
Other Analog Characteristics
Interchannel Gain Mismatch
Gain Drift
Offset Error (Note 13)
High Pass Filter On
High Pass Filter Off
Interchannel Isolation
Full-scale Input Voltage
(Differential Inputs)
1.58•VA
Input Impedance
Common Mode Rejection
(Differential Inputs)
PSRR (Note 14)
1 kHz
60 Hz
-
1.58•VA 1.66•VA 1.74•VA
40
60
-
45
20
-
dB
Vpp
k
dB
dB
dB
Notes:
13. AINx+ connected to AINx-.
14. Valid with the recommended capacitor values on FILT+ and VQ. See Figure 4 for test configuration.
DS899F1
12
CS4234
634 
470 pF
VA
4.7 uF
-
90.9 
CS4234 AINx +
100 k
Analog Signal +
100 k
100 k
+
2700 pF
100 k
100 k
+
Analog Signal 100 k
4.7 uF
CS4234 AINx 90.9 
-
VA
470 pF
634 
Figure 3. Test Circuit for ADC Performance Testing
+Vcc
+Vcc
Operational
Amplifier
Power DAC
DUT
PWR
+
OUT
GND
GND
-Vcc
Analog
Out
- +
- +
OUT
Analog Generator
Digital
Out
- +
Analyzer
Test Equipment
Figure 4. PSRR Test Configuration
DS899F1
13
CS4234
ADC DIGITAL FILTER CHARACTERISTICS
Test Conditions (unless otherwise specified): Device configured as shown in Section 2. on page 8. Input sine
wave: 1 kHz; VA_SEL = 0 for VA = 3.3 VDC, 1 for VA = 5.0 VDC.; TA = -40 to +105 C; Measurement Bandwidth is
20 Hz to 20 kHz unless otherwise specified. See filter plots in Section 7. on page 70.
Parameter (Note 15)
Passband (Frequency Response)
to -0.1 dB corner
Passband Ripple
Min
Typ
Max
Unit
0
-
0.4535
Fs
-0.09
-
0.17
dB
Stopband
0.6
-
-
Fs
Stopband Attenuation
70
-
-
dB
-
9.5/Fs
-
s
Single-Speed Mode
ADC Group Delay (Note 16)
High-Pass Filter Characteristics (48 kHz Fs)
Frequency Response
-3.0 dB
-0.13 dB
-
2
11
-
Hz
Hz
Phase Deviation
@ 20 Hz
-
10
-
Deg
-0.09
-
0.17
dB
-
25000/Fs
-
s
-
9.5/Fs
-
s
-
4
22
-
Hz
Hz
Passband Ripple
Filter Settling Time (Note 17)
Double-Speed Mode
ADC Group Delay (Note 16)
High-Pass Filter Characteristics (96 kHz Fs)
Frequency Response
-3.0 dB
-0.13 dB
Phase Deviation
@ 20 Hz
Passband Ripple
Filter Settling Time (Note 17)
-
10
-
Deg
-0.15
-
0.17
dB
-
25000/Fs
-
s
Note:
15. Response is clock dependent and will scale with Fs.
16. The ADC group delay is measured from the time the analog inputs are sampled on the AINx pins to
the FS/LRCK rising transition after the last bit of that group of samples has been transmitted on
SDOUT1.
17. The amount of time from input of half-full-scale step function until the filter output settles to 0.1% of
full scale.
DS899F1
14
CS4234
ANALOG OUTPUT CHARACTERISTICS
Test Conditions (unless otherwise specified): Device configured as shown in Section 2. on page 8. VA_SEL = 0 for
VA = 3.3 VDC, 1 for VA = 5.0 VDC.; TA = -40 to +105 C; Full-scale 1 kHz input sine wave; Sample Rate = 48 kHz;
Measurement Bandwidth is 20 Hz to 20 kHz; Specifications apply to all channels unless otherwise indicated; all
Power Down DACx bits = 0. See (Note 19).
VA, VREF= 3.3 V
(Differential/Single-ended)
Parameter
VA, VREF= 5.0 V
(Differential/Single-ended)
Min
Typ
Max
Min
Typ
Max
Unit
98/94
95/91
87
84
106/102
103/99
95
92
-
101/97
98/94
87
84
109/105
106/102
95
92
-
dB
dB
dB
dB
-
-90/-88
-82/-80
-
-90/-88
-82/-80
Dynamic Performance
Dynamic Range
18 to 24-Bit
16-Bit
A-weighted
unweighted
A-weighted
unweighted
Total Harmonic Distortion + Noise
1.48•VA/ 1.56•VA/ 1.64•VA/ 1.48•VA/ 1.56•VA/ 1.64•VA/
0.74•VA 0.78•VA 0.82•VA 0.74•VA 0.78•VA 0.82•VA
Full-scale Output Voltage
dB
Vpp
Interchannel Isolation (1 kHz)
-
100
-
-
100
-
dB
Interchannel Gain Mismatch
-
0.1
0.25
-
0.1
0.25
dB
Gain Drift
-
±100
-
-
±100
-
ppm/°C
AC-Load Resistance (RL)(Note 19)
3
-
-
3
-
-
k
Load Capacitance (CL)(Note 19)
-
-
100
-
-
100
pF
10
-
-
10
-
-
k
-
100
-
-
100
-

-
60
60
-
-
60
60
-
dB
dB
Parallel DC-Load Resistance(Note 20)
Output Impedance
PSRR (Note 21)
1 kHz
60 Hz
Notes:
18. One LSB of triangular PDF dither added to data.
19. Loading configuration is given in Figure 5 below.
22 µF
V
OUT
AOUTx
R
L
C
L
GND
Figure 5. Equivalent Output Test Load
20. Parallel combination of all DAC DC loads. See Section 4.2.3.
21. Valid with the recommended capacitor values on FILT+ and VQ. See Figure 4 for test configuration.
DS899F1
15
CS4234
COMBINED DAC INTERPOLATION AND ON-CHIP ANALOG FILTER RESPONSE
Test Conditions (unless otherwise specified): VA_SEL = 0 for VA = 3.3 VDC, 1 for VA = 5.0 VDC. The filter characteristics have been normalized to the sample rate (FS) and can be referenced to the desired sample rate by multiplying the given characteristic by FS. See filter plots in Section 8. on page 71.
Parameter
Single-Speed Mode
Passband (Note 22)
Frequency Response 20 Hz to 20 kHz
StopBand
StopBand Attenuation
DAC1-4 Group Delay (Note 24) (Note 25)
DAC5 Group Delay (Note 25)
(w/ interpolation filter)
(w/ sample and hold)
Low-Latency Group Delay (Note 25)
Double-Speed Mode
Passband (Note 22)
Frequency Response 20 Hz to 20 kHz
StopBand
StopBand Attenuation
DAC1-4 Group Delay (Note 24) (Note 25)
DAC5 Group Delay (Note 25)
(w/ interpolation filter)
(w/ sample and hold)
Low-latency Group Delay (Note 25)
to -0.05 dB corner
to -3 dB corner
(Note 23)
to -0.1 dB corner
to -3 dB corner
(Note 23)
Min
Typ
Max
Unit
0
0
-0.01
0.5465
102
-
11/Fs
0.4780
0.4996
+0.12
-
FS
FS
dB
FS
dB
s
-
11/Fs
2/Fs
2/Fs
-
s
s
s
0
0
-0.05
0.5770
80
-
7/Fs
0.4650
0.4982
+0.2
-
FS
FS
dB
FS
dB
s
-
7/Fs
2.5/Fs
2.5/Fs
-
s
s
s
22. Response is clock dependent and will scale with FS.
23. For Single-Speed Mode, the measurement bandwidth is 0.5465 FS to 3 FS.
For Double-Speed Mode, the measurement bandwidth is 0.577 FS to 1.4 FS.
24. This specification is in addition to any delay added via the “GROUP DELAY[3:0]” bits in the "TPS
Control" register.
25. The DAC group delay is measured from the FS/LRCK rising transition before the first bit of a group of
samples is transmitted on the SDINx pins to the time it appears on the AOUTx pins.
DS899F1
16
CS4234
DIGITAL I/O CHARACTERISTICS
Parameters
High-Level Input Voltage (all input pins except RST)
(% of VL)
(VL = 1.8 V)
High-Level Input Voltage (all input pins except RST)
(% of VL)
(VL = 2.5 V, 3.3 V, or 5 V)
Low-Level Input Voltage (all input pins except RST)
(% of VL)
High-Level Input Voltage (RST pin)
Low-Level Input Voltage (RST pin)
Symbol
Min
Typ
Max
Units
VIH
75%
-
-
V
VIH
70%
-
-
V
VIL
-
-
30%
V
VIH
1.2
-
-
V
VIL
-
-
0.3
V
High-Level Output Voltage at Io = 2 mA
(% of VL)
VOH
80%
-
-
V
Low-Level Output Voltage at Io = 2 mA
(% of VL)
VOL
-
-
20%
V
Iin
-
-
±10
A
-
8
-
pF
Input Leakage Current
Input Capacitance
DS899F1
17
CS4234
SWITCHING CHARACTERISTICS - SERIAL AUDIO INTERFACE
VA_SEL = 0 for VA = 3.3 VDC, 1 for VA = 5.0 VDC.
Parameters
RST pin Low Pulse Width
(Note 26)
MCLK Frequency
MCLK Duty Cycle
SCLK Duty Cycle
Input Sample Rate (FS/LRCK pin)
(Note 27)
Single-Speed Mode
Double-Speed Mode
SCLK Falling Edge to SDOUTx Valid (VL = 1.8 V)
SCLK Falling Edge to SDOUTx Valid (VL = 2.5 V)
SCLK Falling Edge to SDOUTx Valid (VL = 3.3 V or 5 V)
TDM Slave Mode
SCLK Frequency
(Note 28)
FS/LRCK High Time Pulse
(Note 29)
FS/LRCK Rising Edge to SCLK Rising Edge
SDINx Setup Time Before SCLK Rising Edge
SDINx Hold Time After SCLK Rising Edge
PCM Slave Mode
SCLK Frequency
FS/LRCK Duty Cycle
FS/LRCK Edge to SCLK Rising Edge
SDINx Setup Time Before SCLK Rising Edge
SDINx Hold Time After SCLK Rising Edge
PCM Master Mode
SCLK Frequency
FS/LRCK Duty Cycle
FS/LRCK Edge to SCLK Rising Edge
SDINx Setup Time Before SCLK Rising Edge
SDINx Hold Time After SCLK Rising Edge
(VL = 1.8 V)
SDINx Hold Time After SCLK Rising Edge
(VL = 2.5 V, 3.3 V, or 5 V)
Symbol
Min
Units
ms
FS
FS
tdh2
tdh2
tdh2
1
7.68
45
45
30
60
-
Max
25.6
55
55
50
100
31
22
17
MHz
%
%
kHz
kHz
ns
ns
ns
tlpw
256x
1/fSCLK
512x
(n-1)/fSCLK
FS
ns
tlcks
tds
tdh1
5
3
5
-
ns
ns
ns
tlcks
tds
tdh1
32x
45
5
3
5
64x
55
-
FS
%
ns
ns
ns
tlcks
tds
64x
45
5
5
64x
55
-
FS
%
ns
ns
tdh1
11
-
ns
tdh1
10
-
ns
(Note 30)
Notes:
26. After applying power to the CS4234, RST should be held low until after the power supplies and MCLK
are stable.
27. MCLK must be synchronous to and scale with FS.
28. The SCLK frequency must remain less than or equal to the MCLK frequency. For this reason, SCLK
may range from 256x to 512x only in single speed mode. In double speed mode, 256x is the only ratio
supported.
29. The MSB of CH1 is always aligned with the second SCLK rising edge following FS/LRCK rising edge.
30. Where “n” is equal to the MCLK to LRCK ratio (set by the Master Clock Rate register bits), i.e. in 256x
mode, n = 256, in 512x mode, n = 512, etc.
DS899F1
18
CS4234
~
~
~
tLPW
FS/LRCK
(input)
tlcks
SCLK
(input)
tds
tdh1
SDINx
MSB
(input)
tdh2
MSB-1
tdh2
SDOUT1
MSB
(output)
MSB-1
Figure 6. TDM Serial Audio Interface Timing
FS/LRCK
(input/output)
tlcks
SCLK
(input/output)
tds
SDINx
(input)
tdh1
MSB
MSB-1
MSB
MSB-1
tdh2
SDOUTx
(output)
Figure 7. PCM Serial Audio Interface Timing
DS899F1
19
CS4234
SWITCHING SPECIFICATIONS - CONTROL PORT
Test conditions (unless otherwise specified): Inputs: Logic 0 = GND = 0 V, Logic 1 = VL; SDA load capacitance equal to maximum value of Cb specified below (Note 31).
Parameters
Symbol
Min
Max
Unit
SCL Clock Frequency
fscl
-
550
kHz
RESET Rising Edge to Start
tirs
(Note 32)
-
ns
Bus Free Time Between Transmissions
tbuf
1.3
-
µs
Start Condition Hold Time (prior to first clock pulse)
thdst
0.6
-
µs
Clock Low time
tlow
1.3
-
µs
Clock High Time
thigh
0.6
-
µs
tsust
0.6
-
µs
thddi
0
0.9
µs
SDA Output Hold Time from SCL Falling
thddo
0.2
0.9
µs
SDA Setup time to SCL Rising
tsud
100
-
ns
Rise Time of SCL and SDA
tr
-
300
ns
Fall Time SCL and SDA
tf
-
300
ns
tsusp
0.6
-
µs
SDA Bus Load Capacitance
Cb
-
400
pF
SDA Pull-Up Resistance
Rp
500
-

Setup Time for Repeated Start Condition
SDA Input Hold Time from SCL Falling
(Note 33)
Setup Time for Stop Condition
Notes:
31. All specifications are valid for the signals at the pins of the CS4234 with the specified load capacitance.
32. 2 ms + (3000/MCLK). See Section 4.2.1.
33. Data must be held for sufficient time to bridge the transition time, tf, 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 8. I²C Control Port Timing
DS899F1
20
CS4234
4. APPLICATIONS
4.1
Power Supply Decoupling, Grounding, and PCB Layout
As with any high-resolution converter, the CS4234 requires careful attention to power supply and grounding
arrangements if its potential performance is to be realized. Figure 2 shows the recommended power arrangements, with VA connected to clean supplies. VDREG, which powers the digital circuitry, is generated
internally from an on-chip regulator from the VA supply. The VDREG pin provides a connection point for the
decoupling capacitors, as shown in Figure 2.
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 near to the pins of the CS4234 as possible. The low value ceramic capacitor should be the nearest to the pin and should be mounted on the same
side of the board as the CS4234 to minimize inductance effects. All signals, especially clocks, should be
kept away from the FILT+, VBIAS, and VQ pins in order to avoid unwanted coupling into the modulators.
The FILT+, VBIAS, and VQ decoupling capacitors, particularly the 0.1 µF, must be positioned to minimize
the electrical path from their respective pins and GND.
For optimal heat dissipation from the package, it is recommended that the area directly under the device be
filled with copper and tied to the ground plane. The use of vias connecting the topside ground to the backside ground is also recommended.
4.2
Recommended Power-Up and Power-Down Sequence
The initialization and Power-Up/Down sequence flow chart is shown in Figure 9. For the CS4234 Reset is
defined as all lines held static, RST line is pulled low. Power Down is defined as all lines (excluding MCLK)
held static, RST line is high, all PDNx bits are ‘1’. Running is defined as RST line high, all PDNx bits are ‘0’.
4.2.1
Power-up
The CS4234 enters a reset state upon the initial application of VA and VL. When these power supplies
are initially applied to the device, the audio outputs, AOUTxx, are clamped to VQ which is initially low.
Additionally, the interpolation and decimation filters, delta-sigma modulators and control port registers are
all reset and the internal voltage reference, multi-bit digital-to-analog and analog-to-digital converters and
low-pass filters are powered down. The device remains in the reset state until the RST pin is brought high.
Once RST is brought high, the control port address is latched after 2 ms + (3000/MCLK). Until this latching
transition is complete, the device will not respond to I²C reads or writes, but the I²C bus may still be used
during this time. Once the latching transition is complete, the address is latched and the control port is
accessible. At this point and the desired register settings can be loaded per the interface descriptions detailed in the Section 4.3 I²C Control Port. To ensure specified performance and timing, the VA_SEL must
be set to “0” for VA = 3.3 VDC and “1” for VA = 5.0 VDC before audio output begins.
After the RST pin is brought high and MCLK is applied, the outputs begin to ramp with VQ towards the
nominal quiescent voltage. VQ will charge to VA/2 upon initial power up. The time that it takes to charge
up to VA/2 is governed by the size of the capacitor attached to the VQ pin. With the capacitor value shown
in the typical connection diagram, the charge time will be approximately 250 ms. The gradual voltage
ramping allows time for the external DC-blocking capacitors to charge to VQ, effectively blocking the quiescent DC voltage. Once FS/LRCK is valid, MCLK occurrences are counted over one FS period to determine the MCLK/FS ratio. With MCLK valid and any of the PDNx bits cleared, the internal voltage
references will transition to their nominal voltage. Power is applied to the D/A converters and filters, and
the analog outputs are unclamped from the quiescent voltage, VQ. Afterwards, normal operation begins.
DS899F1
21
CS4234
4.2.2
Power-down
To prevent audio transients at power-down, the DC-blocking capacitors must fully discharge before turning off the power. In order to do this in a controlled manner, it is recommended that all the converters be
muted to start the sequence. Next, set PDNx for all converters to 1 to power them down internally. Then,
FS/LRCK and SCLK can be removed if desired. Finally, the “VQ RAMP” bit in the "DAC Control 4" register
must be set to ‘1’ for a period of 50 ms before applying reset or removing power or MCLK. During this
time, voltage on VQ and the audio outputs discharge gradually to GND. If power is removed before this
50 ms time period has passed, a transient will occur and a slight click or pop may be heard. There is no
minimum time for a power cycle. Power may be reapplied at any time.
It is important to note that all clocks should be applied and removed in the order specified in Figure 9. If
MCLK is removed or applied before RST has been pulled low, audible pops, clicks and/or distortion can
result. If either SCLK or FS/LRCK is removed or applied before all PDNx bits are set to “1”, audible pops,
clicks and/or distortion can result.
Note:
Timings are approximate and based upon the nominal value of the passive components specified in the
“Typical Connection Diagram” on page 8. See Section 4.6.6.2 for volume ramp behavior.
DS899F1
22
CS4234
System
Unpowered
Apply VL, VA, and MCLK
Remove VL, VA, and MCLK
250 ms
VQ Ready
(> 90% of Typical)
Set RST
2
2 ms + (3000/MCLK)
Write all required configuration
settings to Control Port
2 ms +
(3000 /MCLK)
I C Address
Captured & Control
Port Ready
Clear RST
50 ms
Set VQ_RAMP bit
Write VA_SEL bit (in 0Fh)
appropriately for VA
250ms
Start SCLK, FS/LRCK, SDINx
Stop SCLK, FS/LRCK, SDINx
Clear PDN DACx & ADCx bits
Set all PDN DAC & ADC bits
Clear reset to SMPS controller
Set PDN_CHx bits
Ramp SMPS rails to +/- 4V
Set reset to SMPS controller
Set RST
delay dependent on
STBY pin RC filter
Write all required configuration
settings to Control Port
Apply logic level low to Mute Pin
and RC network on Standby Pin
Clear PDN_CHx bits
Set MUTE_CHx bits
Apply logic level high to Mute Pin
and RC network on Standby Pin
delay dependent on
STBY pin RC filter
Ramp SMPS rails to +/- 4V
Clear MUTE_CHx bits
delay dependent
on DAC mute /
unmute behavior
Run Speaker Diagnostics by
setting the RUN DIAG bit
(if desired)
Set Mute DAC5 (to SMPS)
delay dependent
on RAMP_DIAG
pin capacitor
Clear Mute DAC5 (to SMPS)
delay dependent
on DAC mute /
unmute behavior
Set Mute ADCx bits
ADC Data
Available on
SDOUT1
Clear Mute ADCx bits
Clear Mute DAC1-4 bits
DAC5 Fully
Operational
delay dependent
on DAC mute /
unmute behavior
DAC1-4 Fully
Operational
delay dependent
on DAC mute /
unmute behavior
Set Mute DAC1-4 bits
CS4234 Control
System
Operational
CS44417 Control
SMPS Control
CS4234 and CS44417 Control
Figure 9. System Level Initialization and Power-up / Power-down Sequence
DS899F1
23
CS4234
4.2.3
DAC DC Loading
Figure 10 shows the analog output configuration during power-up, with the AOUTx± pins clamped to VQ
to prevent pops and clicks. Thus any DC loads (RLx) on the output pins will be in parallel when the switches are closed. These DC loads will pull the VQ voltage down towards ground. If the parallel combination
of all DC loads exceeds the specification shown in the Analog Output Characteristics table, the VQ voltage
will never rise to its minimum operating voltage. If the VQ voltage never rises above this minimum operating voltage, the device will not finish the power-up sequence and normal operation will not begin.
Also note that any AOUTx± pin(s) with a DC load must remain powered up (PDN DACx = 0) to keep the
VQ net at its nominal voltage during normal operation, otherwise clipping may occur on the outputs.
Note that the load capacitors (CLx) are also in parallel during power-up. The amount of total capacitance
on the VQ net during power-up will affect the amount of time it takes for the VQ voltage to rise to its nominal operating voltage after VA power is applied. The time period can be calculated using the time constant
given by the internal series resistor and the load capacitors.
AOUT1+
RL1+
CL1+
RL1-
CL1-
RL2+
CL2+
RL2-
CL2-
RL3+
CL3+
RL3-
CL3-
RL4+
CL4+
RL4-
CL4-
RL5+
CL5+
RL5-
CL5-
S1±
AOUT1-
AOUT2+
S2±
AOUT2VA
~140kΩ
AOUT3+
VQ
NET
S3±
~140kΩ
AOUT3-
External VQ
capacitor
AOUT4+
S4±
AOUT4-
AOUT5+
S5±
AOUT5-
Figure 10. DAC DC Loading
DS899F1
24
CS4234
4.3
I²C Control Port
All device configuration is achieved via the I²C control port registers as described in the Switching Specifications - Control Port table. The operation via the control port may be completely asynchronous with respect
to the audio sample rates. However, to avoid potential interference problems, the I²C pins should remain
static if no operation is required. The CS4234 acts as an I²C slave device.
SDA is a bidirectional data line. Data is clocked into and out of the device by the clock, SCL. The ADx pins
form the least significant bits of the chip address and should be connected through a resistor to VL or GND
as desired. The state of these pins are sensed after the CS4234 is released from reset.
The signal timings for a read and write cycle are shown in Figure 11 and Figure 12. 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 CS4234 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 4 bits of the 7-bit address field are fixed at 0010. To communicate with a CS4234, the chip address
field, which is the first byte sent to the CS4234, should match 0010 followed by the settings of the ADx pins.
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 CS4234 after each input byte is read, and is input to the CS4234 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)
0
SDA
0
1
0
MAP BYTE
AD2 AD1 AD0 0
6
INCR
5 4
3 2 1 0
ACK
7
6
1 0
ACK
DATA +n
DATA +1
DATA
7
6
1 0
7 6
1 0
ACK
ACK
STOP
START
Figure 11. 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
0
0
1
0
AD2 AD1 AD0 0
INCR
ACK
START
STOP
MAP BYTE
6
5
4
3
2
1
0
CHIP ADDRESS (READ)
0
0
1
0
DATA
7
AD2 AD1 AD0 1
ACK
START
ACK
DATA +1
0
7
ACK
0
DATA + n
7
0
NO
ACK
STOP
Figure 12. 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 12, 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 0010xxx0 (chip address and write operation).
Receive acknowledge bit.
Send MAP byte, auto increment off.
DS899F1
25
CS4234
Receive acknowledge bit.
Send stop condition, aborting write.
Send start condition.
Send 0010xxx1 (chip address and read operation).
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.
4.3.1
Memory Address Pointer (MAP)
The MAP byte comes after the address byte and selects the register to be read or written. Refer to the
pseudocode above for implementation details.
4.3.1.1
Map Increment (INCR)
The CS4234 has MAP auto-increment capability enabled by the INCR bit (the MSB) of the MAP. If INCR
is set to ‘0’, MAP will stay constant for successive I²C reads or writes. If INCR is set to ‘1’, MAP will autoincrement after each byte is read or written, allowing block reads or writes of successive registers.
4.4
System Clocking
The CS4234 will operate at sampling frequencies from 30 kHz to 100 kHz. This range is divided into two
speed modes as shown in Table 1.
Mode
Sampling Frequency
Single-Speed
30-50 kHz
Double-Speed
60-100 kHz
Table 1. Speed Modes
The serial port clocking must be changed while all PDNx bits are set. If the clocking is changed otherwise,
the device will enter a mute state, see Section 4.8 on page 47.
4.4.1
Master Clock
The ratio of the MCLK frequency to the sample rate must be an integer. The FS/LRCK frequency is equal
to FS, the frequency at which all of the slots of the TDM stream or channels in Left Justified or I²S formats
are clocked into or out of the device. The Speed Mode and Master Clock Rate bits configure the device
to generate the proper clocks in Master Mode and receive the proper clocks in Slave Mode. Table 2 illustrates several standard audio sample rates and the required MCLK and FS/LRCK frequencies.
The CS4234 has an internal fixed ratio PLL. This PLL is activated when the “MCLK RATE[2:0]” bits in the
"Clock and SP Sel." register are set to either 000 or 001, corresponding to 256x or 384x. When in either
of these two modes, the PLL will activate to adjust the frequency of the incoming MCLK to ensure that the
internal state machines operate at a nominal 24.576 MHz rate. As is shown in the Typical Current Consumption table, activation of the PLL will increase the power consumption of the CS4234.
DS899F1
26
CS4234
FS/LRCK (kHz)
MCLK (MHz)
128x
(Note 34)
192x
(Note 34)
256x
384x
512x
32
-
-
8.1920
12.2880
16.3840
44.1
-
-
11.2896
16.9344
22.5792
48
-
-
12.2880
18.4320
24.5760
64
8.1920
12.2880
16.3840
-
-
88.2
11.2896
16.9344
22.5792
-
-
96
12.2880
18.4320
24.5760
-
-
DSM
Mode
SSM
Table 2. Common Clock Frequencies
Note:
34. 128x and 192x ratios valid only in Left Justified or I²S formats.
4.4.2
Master Mode Clock Ratios
As a clock master, FS/LRCK and SCLK will operate as outputs internally derived from MCLK. FS/LRCK
is equal to FS and SCLK is equal to 64x FS as shown in Figure 13. TDM format is not supported in Master
Mode.
MCLK Rate Bits
÷512
00
÷256
01
FS/LRCK
MCLK
÷1.5
x2
000
x2
001
Speed Mode Bits
010
÷8
00
÷4
01
÷1
SCLK
PLL active
Figure 13. Master Mode Clocking
The resulting valid master mode clock ratios are shown in Table 3 below.
SSM
DSM
MCLK/FS
256x, 384x, 512x
128x, 192x, 256x
SCLK/FS
64x
64x
Table 3. Master Mode Left Justified and I²S Clock Ratios
4.4.3
Slave Mode Clock Ratios
In Slave Mode, SCLK and FS/LRCK operate as inputs. The FS/LRCK clock frequency must be equal to
the sample rate, FS, and must be synchronously derived from the supplied master clock, MCLK.
DS899F1
27
CS4234
The serial bit clock, SCLK, must be synchronously derived from the master clock, MCLK, and be equal to
512x, 256x, 128x, 64x, 48x or 32x FS, depending on the desired format and speed mode. Refer to Table 4
and Table 5 for required clock ratios.
SSM
DSM
MCLK/FS
256x, 384x, 512x
128x, 192x, 256x
SCLK/FS
32x, 48x, 64x, 128x
32x, 48x, 64x
Table 4. Slave Mode Left Justified and I²S Clock Ratios
(Note 35)
SSM
DSM
MCLK/FS
256x, 384x, 512x
512x
256x
SCLK/FS
256x
512x
256x
Table 5. Slave Mode TDM Clock Ratios
Note:
35. For all cases, the SCLK frequency must be less than or equal to the MCLK frequency.
4.5
Serial Port Interface
The serial port interface format is selected by the Serial Port Format register bits. The TDM format is available in Slave Mode only.
4.5.1
TDM Mode
The serial port of the CS4234 supports the TDM interface format with varying bit depths from 16 to 24 as
shown in Figure 15. Data is clocked out of the ADC on the falling edge of SCLK and clocked into the DAC
on the rising edge.
As indicated in Figure 15, TDM data is received most significant bit (MSB) first, on the second rising edge
of the SCLK occurring after a FS/LRCK rising edge. All data is valid on the rising edge of SCLK. All bits
are transmitted on the falling edge of SCLK. Each slot is 32 bits wide, with the valid data sample left justified within the slot. Valid data lengths are 16, 18, 20, or 24 bits.
FS/LRCK identifies the start of a new frame and is equal to the sample rate, FS. As shown in Figure 14,
FS/LRCK is sampled as valid on the rising SCLK edge preceding the most significant bit of the first data
sample and must be held valid for at least 1 SCLK period.
Frame
FS
SCLK
SDINx & SDOUT
Channel 1
Channel 2
Channel N-1
Channel N
(N ≤ 16)
Figure 14. TDM System Clock Format
DS899F1
28
CS4234
32-Bit Channel Block
MSB
-1
-2
-3
-4
-5
-6
-7
+3
+2
+1
LSB
24-Bit Audio Word
8-Bit Zero Pad
(Or DAC5 Data)
Figure 15. 32-bit Receiver Channel Block
The structure in which the serial data is coded into the TDM slots is shown in Figure 16. When using a
48 kHz sample rate with a 24.576 MHz MCLK and SCLK, a 16 slot TDM structure can be realized. When
using a 48 kHz sample rate with 12.288 MHz SCLK and 24.576 MHz MCLK, or a 96 kHz sample rate with
a 24.576 MHz MCLK and SCLK, an 8 slot TDM structure can be realized. The data that is coded into the
TDM slots is extracted into the appropriate signal path via the settings in the Control port. Please refer to
Section 4.6.1 Routing the Serial Data within the Signal Paths for more details.
DS899F1
29
DS899F1
SDOUT with
ADC1
Sidechain Data[31:8]
Input Data
1.1.B
[7:0]
x
[7:0]
0's
[7:0]
0's
[7:0]
Input Data
1.1.A
[31:8]
Input Data
2.1
[31:8]
ADC1 Data
[31:8]
SDIN1
SDIN2
SDOUT
SDOUT with ADC1 Data
[31:8]
Sidechain
…→…
0's
[7:0]
SDOUT
Slot 1 [31:0]
ADC2 Data
[31:8]
0's
[7:0]
ADC1
Data[31:8]
SDIN2
0's
[7:0]
0's
[7:0]
x
[7:0]
0's
[7:0]
FS = 48kHz
x
[7:0]
Output Data
(SDIN2 Slot 4)
Input Data
2.8
[31:8]
x
[7:0]
Slot 8 [31:0]
Input Data
1.8.A
[31:8]
Output Data
(SDIN2 Slot 5)
x
[7:0]
Input Data
1.9.B
[7:0]
0's
[31:0]
Input Data
2.9
[31:8]
Input Data
1.9.A
[31:8]
Slot 9 [31:0]
…→…
x
[7:0]
x
[7:0]
Output Data
(SDIN2 Slot 8)
0's
[31:0]
Input Data
2.12
[31:8]
Input Data
1.12.A
[31:8]
Slot 12 [31:0]
Output Data
(SDIN2 Slot 2)
x[7:0]
Output Data
(SDIN2 Slot 1)
Input Data
2.6
[31:8]
0's
[31:0]
x
[7:0]
Input Data
1.6.B
[7:0]
Slot 6 [31:0]
Input Data
1.6.A
[31:8]
0's
[31:0]
Input Data
2.5
[31:8]
SCLK = 24.576MHz
Output Data
(SDIN2 Slot 1)
…→…
0's
[7:0]
0's
[7:0]
x
[7:0]
Input Data
1.5.B
[7:0]
Slot 5 [31:0]
Input Data
1.5.A
[31:8]
MCLK = 24.576MHz
ADC4 Data
[31:8]
ADC4
Data[31:8]
Input Data
2.4
[31:8]
0's
[31:0]
x
[7:0]
Input Data
1.5.B
[7:0]
0's
[7:0]
0's
[7:0]
x[7:0]
x
[7:0]
Slot 4 [31:0]
Input Data
1.4.A
[31:8]
0's
[31:0]
Input Data
2.5
[31:8]
Input Data
1.5.A
[31:8]
Slot 5 [31:0]
ADC3 Data
[31:8]
ADC3 Data
[31:8]
Input Data
2.3
[31:8]
Input Data
1.3.B
[7:0]
Slot 3 [31:0]
Input Data
1.3.A
[31:8]
x[7:0]
Output Data
(SDIN2 Slot 9)
x
[7:0]
Input Data
1.13.B
[7:0]
0's
[31:0]
Input Data
2.13
[31:8]
Input Data
1.13.A
[31:8]
Slot 13 [31:0]
Output Data
(SDIN2 Slot 3)
0's
[31:0]
Input Data
2.7
[31:8]
x[7:0]
x
[7:0]
x
[7:0]
Output Data
(SDIN2 Slot 12)
0's
[31:0]
Input Data
2.16
[31:8]
Input Data
1.16.A
[31:8]
Slot 16 [31:0]
Output Data
(SDIN2 Slot 4)
0's
[31:0]
Input Data
2.8
[31:8]
x[7:0]
Slot 8 [31:0]
Input Data
1.8.A
[31:8]
…→…
Input Data
1.7.B
[7:0]
Slot 7 [31:0]
Input Data
1.7.A
[31:8]
Figure 16. Serial Data Coding and Extraction Options within the TDM Streams
ADC4 Data
[31:8]
0's
[7:0]
x
[7:0]
Input Data
2.4
[31:8]
ADC4 Data
[31:8]
x
[7:0]
Input Data
1.4.A
[31:8]
Slot 4 [31:0]
ADC2 Data
[31:8]
Input Data
2.2
[31:8]
x
[7:0]
Input Data
2.1
[31:8]
SDIN1
Input Data
1.2.B
[7:0]
Slot 2 [31:0]
Input Data
1.2.A
[31:8]
Input Data
1.1.B
[7:0]
Slot 1 [31:0]
Input Data
1.1.A
[31:8]
SCLK = 12.288/24.576MHz
FS = 48/96kHz
MCLK = 12.288/24.576MHz
CS4234
30
CS4234
4.5.2
Left Justified and I²S Modes
The serial port of the CS4234 supports the Left Justified and I²S interface formats with valid bit depths of
16, 18, 20, or 24 bits for the SDOUTx pins and 24 bits for the SDINx pins. All data is valid on the rising
edge of SCLK. Data is clocked out of the ADC on the falling edge of SCLK and clocked into the DAC on
the rising edge. In Master Mode each slot is 32 bits wide.
In Left Justified mode (see Figure 17) the data is received or transmitted most significant bit (MSB) first,
on the first rising edge of the SCLK occurring after a FS/LRCK edge. The left channel is received or transmitted while FS/LRCK is logic high.
In I²S mode (see Figure 18) the data is received or transmitted most significant bit (MSB) first, on the second rising edge of the SCLK occurring after a FS/LRCK edge. The left channel is received or transmitted
while FS/LRCK is logic low.
The AIN1 and AIN2 signals are transmitted on the SDOUT1 pin; the AIN3 and AIN4 signals are transmitted on the AD2/SDOUT2 pin. The data on the SDIN1 pin is routed to AOUT1 and AOUT2; the data on the
SDIN2 pin is routed to AOUT3 and AOUT4. AOUT5 is unavailable in these modes and should be placed
in the powered down state by using the appropriate Power Down DACx register bit. If it is powered up in
these modes, the AOUT5 output will be active and may drive an AC or DC signal.
FS/LRCK
SCLK
SDINx
SDOUTx
L e ft C h a n n e l
M SB
R ig h t C h a n n e l
LS B
MSB
LS B
MSB
AOUT 2 or 4
AIN 2 or 4
AOUT 1 or 3
AIN 1 or 3
Figure 17. Left Justified Format
FS/LRCK
L e ft C h a n n e l
R ig h t C h a n n e l
SCLK
SDINx
SDOUTx
M SB
LS B
M SB
LS B
MSB
AOUT 2 or 4
AIN 2 or 4
AOUT 1 or 3
AIN 1 or 3
Figure 18. I²S Format
DS899F1
31
CS4234
4.6
Internal Signal Path
VA
5.0 VDC
VD
2. 5 VDC
-1 -2
2.5 V
Gain / Volume
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert ,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elect
Mode
Select
DC Offset
X

Full Scale Code
Master Volume
0 dB
Filter
Select
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
5 th DAC
Input Advisory
(±)
(±)
(±)
(±)
Multi-bit
 ADC
Group
Delay
0-500uS
Digital Filters
Low -Latency
Demux
Channel Volume ,
Mute, Invert ,
Noise Gate
Master
Volume
Control
Mute, Invert ,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Control )
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
TDM Serial Interface
Control Port
Level Translator
SDOUTx
VL
1.8 to 5.0 VDC
SDIN 2
Frame Sync
Clock / LRCK
SDIN1
Master Clock In
Serial Clock
In / Out
INT
RST
2
I C Control
Data
Figure 19. Audio Path Routing
The CS4234 device includes four main paths in which audio data can be routed. The analog input path,
shown in yellow, allows up to four analog signals to be combined into a single TDM stream on the SDOUT1
pin or output as stereo pairs on the SDOUT1 and SDOUT2 pins. The DAC1-4 path, highlighted in blue, converts serial audio data to analog audio data. The DAC5 path is highlighted in red and can be used to create
a tracking power supply signal, to convert a digital tracking power supply signal to analog, or as a standard
audio CODEC with performance characteristics identical to the DACs found in the DAC1-4 path. Group delay will often be added to the DAC1-4 path to allow the tracking power supply signal to lead the audio signal.
A low-latency path is provided as well to allow signals which should not be delayed to be mixed together
with the output signal at a point after the group delay block. The low-latency path is shown in green.
4.6.1
Routing the Serial Data within the Signal Paths
The serial port in the CS4234 is highly versatile and allows a number of ways that the serial data can be
coded into and extracted out of the TDM slots on the SDINx pins. Because of its versatility, it is possible
to errantly route the serial data into several of the available data paths. This mode of operation is not supported in the CS4234 and should not be used.
4.6.1.1
ADC Signal Routing
In TDM mode, the CS4234 is designed to load the first four slots of the TDM stream on the SDOUT1 pin
with the internal ADC data. Additionally, in order to minimize the number of SDOUT1 lines that must be
run to the system controller in a multiple IC application, the SDOUT1 data for up to 4 devices can be loaded into a single TDM stream by side chaining the devices together, as shown in Figure 20. To enable the
sidechain feature, the “SDO CHAIN” bit in the "SP Control" register must be set.
In Left Justified or I²S mode, the CS4234 transmits the AIN1 and AIN2 signals on the SDOUT1 pin and
the AIN3 and AIN4 signals on the SDOUT2 pin.
DS899F1
32
CS4234
DSP
DSP
Device D
x
Device D
SDOUT1
x
SDIN2
x
SDIN1
x
Each of the device’s ADC data
is reflected in the TDM stream
on SDOUT1 and then routed to
the system controller.
x
SDIN2
x
SDIN1
Device C
x
SDOUT1
SDOUT1
Device C
x
SDOUT1
x
SDIN2
x
SDIN2
x
SDIN1
x
SDIN1
Device B
x
SDOUT1
The ADC data of Device D is coded into the
first four slots of the output TDM stream,
followed by the first 12 slots of the TDM
stream coming in on SDIN2, placing the
ADC data from Device C into slots 5-8, the
ADC data from Device B into slots 9-12, and
the ADC data from Device A into slots 13-16
of the outgoing TDM stream.
The ADC data of Device C is coded into the
first four slots of the output TDM stream,
followed by the first 12 slots of the TDM
stream coming in on SDIN2, placing the
ADC data from Device B into slots 5-8 and
the ADC data from Device A into slots 9-12
of the outgoing TDM stream.
Device B
x
SDOUT1
x
SDIN2
x
SDIN2
x
SDIN1
x
SDIN1
Device A
The ADC data of Device B is coded into the
first four slots of the output TDM stream,
followed by the first 12 slots of the TDM
stream coming in on SDIN2, placing the
ADC data from Device A into slots 5-8 of the
outgoing TDM stream.
Device A
x
SDOUT1
x
SDOUT1
x
SDIN2
x
SDIN2
x
SDIN1
x
SDIN1
ADC data from Device A is loaded into the
first 4 slots of the 16 slot TDM Stream
going out of the SDOUT1 pin of Device A .
The last 12 slots are all coded as “ 0's”.
Note:
This diagram shows the configuration for 16 slot TDM streams. If 8 slot TDM streams are used, two separate serial data lines will need to be
connected from the DSP. One would carry the serial data for Devices C&D and the other would carry the serial data for Devices A&B
Figure 20. Conventional SDOUT1 (Left) vs. Sidechain SDOUT1 (Right) Configuration
4.6.1.2
DAC1-4, DAC5, and Low-latency Signal Routing
In TDM mode, each of the 3 output paths have a collection of bits that advise the CS4234 where data for
each of the paths is located within the incoming TDM streams. For the DAC1-4 path, the bits are “DAC14 SOURCE[2:0]” bits in the "SP Data Sel." register. For the DAC5 path, the bits are the “DAC5
SOURCE[2:0]” bits in the "SP Control" register. Finally, for the Low-Latency Path, the bits are the “LL
SOURCE[2:0]” bits in the "SP Data Sel." register. Details for these registers and the setting of their respective bits can be found in Figure 21 and Figure 22.
In Left Justified or I²S mode, the CS4234 routes the data on the SDIN1 pin to DAC1 and DAC2 and the
data on the SDIN2 pin to DAC3 and DAC4. DAC5 is unavailable in the PCM modes and should be placed
in the powered down state by using the appropriate Power Down DACx register bit. If it is powered up in
these modes, the DAC5 output will be active and may drive an AC or DC signal.
DS899F1
33
DS899F1
Slots 13-16 of SDIN2
111
Slot 1 [31: 0]
Slot 1 [31: 0]
SDIN1
SDIN2
…→…
Slots 9-12 of SDIN2
110
Slot 5 [31:0]
Slot 5 [31:0]
Slot 3 [31:0]
Slot 3 [31:0]
…→…
Slot 8 [31:0]
Slot 8 [31:0]
SCLK = 24 .576 MHz
FS/LRCK = 48 kHz
MCLK = 24.576MHz
Slot 4 [31:0]
Slot 9 [31:0]
Slot 9 [31:0]
Slot 5 [31:0]
SCLK = 12.288/24.576MHz
Slot 4 [31:0]
Slot 5 [31:0]
MCLK = 12.288/24.576MHz
FS/LRCK = 48/96kHz
Slots 13-16 of SDIN2
Slots 9-12 of SDIN2
110
111
Slots 5-8 of SDIN2
101
Slots 1-4 of SDIN2
Slots 13-16 of SDIN1
011
100
Slots 9-12 of SDIN1
Slots 5-8 of SDIN1
Slots 1-4 of SDIN1
Low Latency Data is in:
001
010
000
LL Source [2:0]
…→…
Coded into the LSBs of Slots 13-15 of SDIN1
Determined by the Masking bits
001
010
011
100
Slot 12 [31:0]
Slot 12 [31:0]
Slot 6 [31:0]
Slot 6 [31:0]
Slot 13 [31 :0]
Slot 13 [31 :0]
Slot 7 [31:0]
…→…
Reserved
Reserved
110
111
Reserved
101
Slot 16 [31:0]
Slot 16 [31:0]
Slot 8 [31:0]
Slot 8 [31:0]
Coded into the LSBs of Slots 5-7 of SDIN1
Coded into the LSBs of Slots 9-11 of SDIN1
000
Slot 7 [31:0]
DAC5 Data is in:
Coded into the LSBs of Slots 1-3 of SDIN1
DAC5 Source [2:0]
Figure 21. DAC1-4, Low Latency, and DAC5 Path Serial Data Source Selection
Slot 4 [ 31:0]
Slot 4 [ 31:0]
Slot 2 [31:0]
Slots 5-8 of SDIN2
101
Slot 1 [31:0]
Slots 1-4 of SDIN2
100
SDIN2
Slots 13-16 of SDIN1
011
Slot 2 [31:0]
Slots 5-8 of SDIN1
Slots 9-12 of SDIN1
001
010
Slot 1 [31:0]
Slots 1-4 of SDIN1
000
SDIN1
DAC1-4 Data is in:
DAC1-4 Source [2:0]
CS4234
34
DS899F1
Slots 5-8 of SDIN1
Slots 9-12 of SDIN1
Slots 13-16 of SDIN1
Slots 1-4 of SDIN2
Slots 5-8 of SDIN2
Slots 9-12 of SDIN2
Slots 13-16 of SDIN2
001
010
011
100
101
110
111
SDIN2
Slots 5-8 of SDIN1
Slots 9-12 of SDIN1
Slots 13-16 of SDIN1
Slots 1-4 of SDIN2
Slots 5-8 of SDIN2
Slots 9-12 of SDIN2
Slots 13-16 of SDIN2
001
010
011
100
101
110
111
DAC5 [23:0]
x
SDIN1
SDIN2
x
x
x
Slot 2 [31:0]
Slots 1-4 of SDIN1
000
Slot 1 [31:0]
DAC1-4 Data is in:
DAC1-4 Source [2:0]
LL4 [23 :0]
x
x
Slot 4 [31:0]
LL1 [23:0]
DAC1 [23:0]
x
x
Slot 5 [31:0]
FS/LRCK = 48/96kHz
SCLK = 12.288/24.576MHz
MCLK = 12.288/24.576MHz
Slots 13-16 of SDIN2
Slots 9-12 of SDIN2
110
Slots 1-4 of SDIN2
Slots 13-16 of SDIN1
Slots 9-12 of SDIN1
Slots 5-8 of SDIN1
Slots 1-4 of SDIN1
Slots 5-8 of SDIN2
111
x
x
Slot 5 [31:0 ]
Low Latency Data is in:
x
x
LL2 [23:0]
DAC2 [23:0]
x
x
Slot 6 [31:0]
111
110
101
100
011
001
010
000
DAC5 Data is in:
DAC5 Data is in:
x
x
Slot 8 [31 :0]
LL3 [23:0]
x
x
Slot 7 [31:0]
LL4 [23:0]
DAC4 [23:0]
x
x
Slot 8 [31:0]
Reserved
Reserved
Reserved
Determined by the Masking bits
Coded into the LSBs of Slots 13-15 of SDIN1
Coded into the LSBs of Slots 9-11 of SDIN1
Coded into the LSBs of Slots 5-7 of SDIN1
Coded into the LSBs of Slots 1-3 of SDIN1
x
x
Slot 7 [31:0 ]
Reserved
Reserved
Reserved
Determined by the Masking bits
Coded into the LSBs of Slots 13-15 of SDIN1
Coded into the LSBs of Slots 9-11 of SDIN1
Coded into the LSBs of Slots 5-7 of SDIN1
Coded into the LSBs of Slots 1-3 of SDIN1
DAC3 [23:0]
DAC5 Source [2:0]
x
x
Slot 6 [31 :0]
111
110
101
100
011
001
010
000
DAC5 Source [2:0]
Figure 22. Example Serial Data Source Selection
x
x
FS/LRCK = 48/96kHz
SCLK = 12 .288 /24 .576MHz
Slot 4 [31:0]
101
100
011
001
010
000
Slots 13-16 of SDIN2
Slots 9-12 of SDIN2
Slots 5-8 of SDIN2
Slots 1-4 of SDIN2
Slots 13-16 of SDIN1
Slots 9-12 of SDIN1
Slots 5-8 of SDIN1
Slots 1-4 of SDIN1
Low Latency Data is in:
MCLK = 12.288 /24 .576 MHz
DAC4 [23 :0]
LL Source [2:0]
x
DAC5 [7:0]
Slot 3 [31:0]
LL3 [23:0]
x
LL1 [ 23:0]
LL2 [23 :0]
DAC3 [23:0 ]
DAC1 [23:0 ] DAC5 [23 :16] DAC2 [23 :0] DAC5 [15 :8]
x
111
110
101
100
011
001
010
000
LL Source [2:0]
Slot 3 [31:0]
SDIN1
Slot 2 [31 :0]
Slots 1-4 of SDIN1
000
Slot 1 [ 31:0]
DAC1-4 Data is in:
DAC1-4 Source [2:0]
CS4234
35
CS4234
As can be seen from Figure 22, setting ‘100’ of the DAC5 Source[2:0] bits configures the DAC5 path to
use the mask bits to determine which signals are routed into the DAC5 path. The CS4234 is designed to
make any one of the slots of both the SDINx pins available to the 5th DAC Input Advisory block, where the
mask bits for the DAC5 path are located. The configuration of the mask bits is shown in Table 6 and
Table 7. In order to unmask a slot from the DAC5 path, a ‘0’ must be written to the appropriate bit within
the appropriate mask register.
SDIN1
Mask 1[7:0]
Setting
Data to be Unmasked from
DAC5 Path
x
x
x
SDIN1
Mask 2[7:0]
Setting
SDIN1 Slot 1
0
x
x
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 2
x
0
x
x
x
x
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 3
x
x
0
x
x
x
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 4
x
x
x
0
x
x
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 5
x
x
x
x
0
x
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 6
x
x
x
x
x
0
x
x
x
x
x
x
x
x
x
x
SDIN1 Slot 7
x
x
x
x
x
x
0
x
x
x
x
x
x
x
x
x
SDIN1 Slot 8
x
x
x
x
x
x
x
0
x
x
x
x
x
x
x
x
SDIN1 Slot 9
x
x
x
x
x
x
x
x
0
x
x
x
x
x
x
x
SDIN1 Slot 10
x
x
x
x
x
x
x
x
x
0
x
x
x
x
x
x
SDIN1 Slot 11
x
x
x
x
x
x
x
x
x
x
0
x
x
x
x
x
SDIN1 Slot 12
x
x
x
x
x
x
x
x
x
x
x
0
x
x
x
x
SDIN1 Slot 13
x
x
x
x
x
x
x
x
x
x
x
x
0
x
x
x
SDIN1 Slot 14
x
x
x
x
x
x
x
x
x
x
x
x
x
0
x
x
SDIN1 Slot 15
x
x
x
x
x
x
x
x
x
x
x
x
x
x
0
x
SDIN1 Slot 16
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
0
Table 6. Unmasking SDIN1 Data from DAC5 Path
DS899F1
36
CS4234
SDIN2
Mask 1[7:0]
Setting
Data to be Unmasked from
DAC5 Path
x
x
x
SDIN2
Mask 2[7:0]
Setting
SDIN2 Slot 1
0
x
x
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 2
x
0
x
x
x
x
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 3
x
x
0
x
x
x
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 4
x
x
x
0
x
x
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 5
x
x
x
x
0
x
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 6
x
x
x
x
x
0
x
x
x
x
x
x
x
x
x
x
SDIN2 Slot 7
x
x
x
x
x
x
0
x
x
x
x
x
x
x
x
x
SDIN2 Slot 8
x
x
x
x
x
x
x
0
x
x
x
x
x
x
x
x
SDIN2 Slot 9
x
x
x
x
x
x
x
x
0
x
x
x
x
x
x
x
SDIN2 Slot 10
x
x
x
x
x
x
x
x
x
0
x
x
x
x
x
x
SDIN2 Slot 11
x
x
x
x
x
x
x
x
x
x
0
x
x
x
x
x
SDIN2 Slot 12
x
x
x
x
x
x
x
x
x
x
x
0
x
x
x
x
SDIN2 Slot 13
x
x
x
x
x
x
x
x
x
x
x
x
0
x
x
x
SDIN2 Slot 14
x
x
x
x
x
x
x
x
x
x
x
x
x
0
x
x
SDIN2 Slot 15
x
x
x
x
x
x
x
x
x
x
x
x
x
x
0
x
SDIN2 Slot 16
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
0
Table 7. Unmasking SDIN2 Data from DAC5 Path
Due to the flexibility of the DAC5 path, it is possible to errantly unmask several data slots simultaneously.
If this occurs and DAC5 is not in Tracking Power Supply mode (see Section 4.6.5.1 Generating the Tracking Signal Inside the CS4234), only one data slot will be taken as the input into the DAC5 path. The selection of this data slot is based upon the priority level of each of the slots which have been unmasked.
The priority structure is as follows:
1. Slot 1 of SDIN 1 receives 1st priority
2. Slot 2 of SDIN 1 receives 2nd priority
3. ...
4. Slot 16 of SDIN 1 receives 16th priority
5. Slot 1 of SDIN 2 receives 17th priority
6. ...
7. Slot 16 of SDIN 2 receives last priority.
DS899F1
37
CS4234
4.6.2
ADC Path
VD
2.5 VDC
VA
5. 0 VDC
-1 -2
2.5 V
DC Offset
Gain / Volume
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert ,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elec t
Mode
Select
X

Full Scale Code
Master Volume
Filter
Select
0 dB
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
5 th DAC
Input Advisory
(±)
(±)
(±)
(±)
Multi-bit
 ADC
Group
Delay
0-500uS
Low -Latency
Demux
Digital Filters
Channel Volume ,
Mute, Invert ,
Noise Gate
Master
Volume
Control
Mute, Invert ,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Contro
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
Serial Audio Interface
Control Port
Level Translator
SDOUTx
SDIN 2
SDIN1
Frame Sync
Clock / LRCK
Master Clock In
VL
1.8 to 5.0 VDC
Serial Clock
In / Out
INT
RST
2
I C Control
Data
Figure 23. ADC Path
4.6.2.1
Analog Inputs
AINx+ and AINx- are line-level differential analog inputs. The analog input pins do not self-bias and must
be externally biased to VA/2 to avoid clipping of the input signal. The full-scale analog input levels are
scaled according to VA and can be found in the Analog Input Characteristics table.
The ADC output data is in two’s complement binary format. For inputs above positive full scale or below
negative full scale, the ADC will output 7FFFFFH or 800000H, respectively, and cause the ADC Overflow
bit in the Interrupt Notification 1 register to be set to a ‘1’.
When used with the CS44417, whose current monitoring circuitry is single ended, the CS4234’s AINxnets should be joined together and connected to the VQ output from the CS44417. This connection will
prevent any variances in the reference voltages of the CS4234 and the CS44417 from skewing the
CS44417 output current measurements. Refer to Figure 2 for more details concerning these connections.
4.6.2.2
ADC HPF
The ADC path has an optional HPF which can be enabled or disabled for all four ADCs via the “ENABLE
HPF” bit in the "ADC Control 1" register. The HPF should only be disabled when the DC component of
the input signal needs to be preserved in the digital output data (i.e. current monitoring with the CS44417).
The HPF characteristics are given in the ADC Digital Filter Characteristics table and plotted in Section 7.
The Analog Input Characteristics table specifies the DC offset error when the HPF is enabled or disabled.
DS899F1
38
CS4234
4.6.3
DAC1-4 Path
VA
5.0 VDC
VD
2.5 VDC
-1 -2
2.5 V
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elec t
Mode
Select
DC Offset
Gain / Volume
X

Full Scale Code
Master Volume
0 dB
Filter
Select
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
5 th DAC
Input Advisory
(±)
(±)
(±)
(±)
Multi-bit
 ADC
Group
Delay
0-500uS
Low -Latency
Demux
Digital Filters
Channel Volume ,
Mute, Invert,
Noise Gate
Master
Volume
Control
Mute, Invert,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Control )
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
Serial Audio Interface
Control Port
Level Translator
SDOUTx
SDIN 2
SDIN1
Frame Sync
Clock / LRCK
Master Clock In
VL
1.8 to 5.0 VDC
Serial Clock
In / Out
INT
RST
2
I C Control
Data
Figure 24. DAC1-4 Path
The AOUT1-4 signals are driven by the data placed into the DAC1-4 path. This data can be placed into
the DAC1-4 path via the DAC1-4 Data Source settings in the control port. These settings allow the input
source to be selected from any of the up to 32 slots of data on the incoming TDM streams on SDIN1 and
SDIN2.
The DAC1-4 path includes a programmable group delay which delays the output audio signals to allow
the DAC5 output to operate in feed-forward fashion, adjusting the voltage rails of the tracking power supply in anticipation of the coming audio signal. There is a connection between the group delay applied to
the audio signal and the ability of the SMPS to respond to high amplitude transients. By having a shorter
delay, the output voltage of the SMPS can track the audio signal more closely, increasing efficiency of the
Class H system. However, providing too short of a delay may prevent the SMPS to react fast enough to
high-amplitude transients, resulting in clipping of the output signal. For these reasons, the group delay of
the CS4234 can be adjusted from 100 s to 500 s, based on the settings of Group Delay bits. The group
delay should only be modified while all of the “Power Down ADCx” bits in the "ADC Control 2 (Address
10h)" register and the “Power Down DACx” bits in the "DAC Control 4 (Address 15h)" register are set to
‘1’b and the DAC outputs have entered the mute state (see Table 8 for mute ramp time when soft-ramp
is enabled). Note that the “Base Rate Advisory” bits in the "Clock and SP Select (Address 06h)" register
must be set to correctly calculate the selected group delay.
The DAC1-4 path also includes individual channel mutes. Separate volume controls are available for each
channel, along with a master volume control that simultaneously attenuates all four channels. The master
volume attenuation is added to any channel attenuation that is applied.
4.6.3.1
De-emphasis Filter
The CS4234 includes on-chip digital de-emphasis for 32, 44.1, and 48 kHz sample rates. It is not supported for 96 kHz or for any settings in Double-speed Mode. The filter response is adjusted to be appropriate
for a particular base rate by the Base Rate Advisory bits. This filter response, shown in Figure 25, will vary
if these bits are not set appropriately for the given base rate. The frequency response of the de-emphasis
curve scales proportionally with changes in sample rate, FS. Please see Section 6.15.2 DAC1-4 De-emphasis for de-emphasis control.
DS899F1
39
CS4234
The de-emphasis feature is included to accommodate audio recordings that utilize 50/15 s preemphasis
equalization as a means of noise reduction.
De-emphasis is only available in Single-speed Mode.
Gain
dB
T1=50 µs
0dB
T2 = 15 µs
-10dB
F1
3.183 kHz
F2
Frequency
10.61 kHz
Figure 25. De-emphasis Curve
4.6.4
Low-Latency Path
VD
2.5 VDC
VA
5.0 VDC
-1 -2
2.5 V
DC Offset
Gain / Volume
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elect
Mode
Select
X

Full Scale Code
Master Volume
0 dB
Filter
Select
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
(±)
(±)
(±)
(±)
5 th DAC
Input Advisory
Multi-bit
 ADC
Group
Delay
0-500uS
Low -Latency
Demux
Digital Filters
Channel Volume ,
Mute, Invert,
Noise Gate
Master
Volume
Control
Mute, Invert,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Control )
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
Serial Audio Interface
Control Port
Level Translator
SDOUTx
SDIN 2
SDIN1
Frame Sync
Clock / LRCK
Master Clock In
Serial Clock
In / Out
VL
1.8 to 5.0 VDC
INT
RST
I2C Control
Data
Figure 26. Low-latency Path
A low-latency path is provided to allow four user selectable data signals to be routed around the group
delay block and interpolation filters of the DAC1-4 path. These four signals can be present in any of the
32 slots on the two TDM streams on SDIN1 and SDIN2.
The Low-Latency path also includes a global mute bit and individual channel invert bits. The signals from
the low latency path are summed with the DAC1-4 path after the master volume control. Changes to the
master volume control setting do not affect the low-latency-path signals. For details concerning the operation of the volume control, please see Section 4.6.6 Volume Control.
DS899F1
40
CS4234
4.6.5
DAC5 Path
VD
2.5 VDC
VA
5.0 VDC
-1 -2
2.5 V
Gain / Volume
Tracking
SMPS
Enable
Max
Detect
Envelope
Tracking
Mute, Invert,
Noise Gate
TPS
GAIN
X
DAC
Volume
X
Master
Vol . Cntrl
Select
LDO
Gain
S elect
Mode
Select
DC Offset
X

Full Scale Code
Master Volume
0 dB
Filter
Select
Interpolation Filter
Multi-bit 
Modulators
Sample & Hold
AIN1
AIN2
AIN3
AIN4
5 th DAC
Input Advisory
(±)
(±)
(±)
(±)
Multi-bit
 ADC
Group
Delay
0-500uS
Low -Latency
Demux
Digital Filters
Channel Volume ,
Mute, Invert,
Noise Gate
Master
Volume
Control
Mute, Invert,
Noise Gate
Analog Supply

Interpolation
Filter



Multi-bit 
Modulators
DAC &
Analog
Filters
DAC &
Analog
Filters
AOUT 5 (±)
(SMPS Control )
AOUT1
AOUT2
AOUT3
AOUT4
(±)
(±)
(±)
(±)
Sample
& Hold
Serial Audio Interface
Control Port
Level Translator
SDOUTx
SDIN 2
SDIN1
Frame Sync
Clock / LRCK
Master Clock In
Serial Clock
In / Out
INT
VL
1.8 to 5.0 VDC
RST
I2C Control
Data
Figure 27. DAC5 Path
The 5th DAC in the CS4234 is a fully functional audio-grade DAC with performance specifications identical
to that of the other four DACs. In addition to the standard feature set, such as independent channel volume and muting, the 5th DAC can also be used to create a reference signal for an off-chip tracking power
supply. This functionality allows any Class AB amplifier to be operated as a Class H amplifier.
Within the DAC5 path, there are several routing options, primarily based upon which parts of the tracking
signal (if any) will be generated within the CS4234 or in an external DSP.
4.6.5.1
Generating the Tracking Signal Inside the CS4234
To generate the tracking signal internally, up to 32 channels of data present in the two TDM streams on
SDIN1 and SDIN2 can be considered. The max detect block determines the largest data sample on a
sample by sample basis. It then holds that sample for a period of time equal to that set in the group delay
block, effectively tracking the envelope of that calculated signal.
Set the “DAC5 CFG & FLTR[1:0]” bits in the "DAC Control 1" register to ‘10’ to select that the tracking
signal is to be generated within the CS4234. To include a channel of data in the calculation, unmask its
respective bit in the SDINx MASKx register. When the Tracking SMPS Enable bit is set, the signal can
not be inverted using the INV DAC5 bit.
In order to compensate for the difference between the gain of the Class AB amplifier stage and the gain
of the switch-mode power supply that generates the rails for the Class AB amplifier, the internal volume
block in the DAC5 path can be adjusted by changing the "DAC5 Volume" register.
Voltage is customarily added to the rails of a Class H amplifier to prevent clipping events from occurring
during high amplitude transients. This DC offset is accomplished within the CS4234 via the“TPS OFFSET[2:0]” bits in the "TPS Control" register.
See Appendix A: Internal Tracking Power Supply Signal for more detailed information about the internal
tracking signal.
DS899F1
41
CS4234
4.6.5.2
Generating the Tracking Signal Inside an External DSP
If the tracking signal is to be generated within an external DSP, the tracking signal generation blocks mentioned above can be bypassed by setting the “DAC5 CFG & FLTR[1:0]” bits in the "DAC Control
1" register to either the interpolation filter option (‘00’) or the sample and hold filter (’01’). Note that the
DAC5 signal inversion caused by setting the “TPS MODE” bit in the "TPS Control" register is not bypassed and for most cases the bit should be cleared, see Figure 29. The “DAC5 SOURCE[2:0]” bits in the
"SP Control" register advise the CS4234 where the tracking signal can be found among the incoming data. If the tracking signal has been coded into one of the 32 slots of the TDM stream, the signal can be
routed into the DAC5 path by masking all of the other slots via the SDINx Maskx bits. As shown in the
“DAC5 SOURCE[2:0]” bits in the "SP Control" register, the tracking signal can also be coded into the
LSBs of the 16 slots of the SDIN1 stream.
4.6.5.3
Using DAC5 in a Traditional DAC Configuration (with no tracking signal)
As mentioned previously, DAC5 is identical in performance to the DACs in the DAC1-4 path. In this application, signal is routed into the DAC5 path in the same manner as in the previous section. If the data for
DAC5 is in one of the 32 slots, simply unmask the appropriate slot by using the appropriate mask bits. If
the data is coded into the LSBs of SDIN1, set the “DAC5 SOURCE[2:0]” bits in the "SP Control" register
appropriately.
Please refer to Section 4.6.6 Volume Control regarding volume control within the DAC5 path. The operation is identical to the volume control in the DAC1-4 path.
One additional control that is present within the DAC5 path is the “DAC5 MVC” bit in the "DAC Control
1" register. When this bit is set, the CS4234 will apply any gain written to the master volume control register to the DAC5 path as well. If this bit is cleared, the DAC5 volume will operate independently of the
setting of the master volume control register. This feature is provided to ensure that, when not desired,
any changes made to the master volume control on the audio path will not affect the output amplitude of
the tracking power supply signal, when DAC5 is used for that application.
4.6.5.4
De-emphasis Filter
The CS4234 includes on-chip digital de-emphasis for 32, 44.1, and 48 kHz sample rates. It is not supported for 96 kHz or for any settings in Double Speed Mode. The filter response is adjusted to be appropriate
for a particular sample rate by the Base Rate Advisory bits. This filter response, shown in Figure 25, will
vary if these bits are not set appropriately for the given sample rate. The frequency response of the deemphasis curve scales proportionally with changes in sample rate, FS. Please see Section 6.15.3 DAC5
De-emphasis for de-emphasis control.
The de-emphasis feature is included to accommodate audio recordings that utilize 50/15 s preemphasis
equalization as a means of noise reduction.
4.6.5.5
Filter Options
There are two internal filter options for the DAC5 path. A standard interpolation filter is provided for traditional applications as well as a “sample and hold” bypass option. To activate the bypass, set the “DAC5
CFG & FLTR[1:0]” bits in the "DAC Control 1" register to ‘01’.
4.6.6
Volume Control
The CS4234 includes a volume control for the DAC1-4 and DAC5 signal paths. While the general operation of the volume controls is identical between the two paths, the optional tracking power supply control
present in the DAC5 path modifies the implementation slightly. The implementation details for the volume
DS899F1
42
CS4234
control and other associated peripheries for DAC1-4 is shown in Figure 28 below. The implementation details for the volume control and other associated peripheries for the DAC5 path is shown in Figure 29.
INV. DACx
DACx Data
1
0
DAC1-4 Noise
Gate Threshold
Noise Gate
Interpolation
Filter
x
DACx Volume
Register Setting
Limiter
(+6 to -90 dB)
+
Master Volume
Register Setting
Soft Ramp
+
Modulator
AOUTx
DAC
0
1
MUTE DACx
DAC1-4 ATT
LL Noise Gate
Threshold
Low Latency
Data
1
0
Noise Gate
MUTE LL
INV. DACx
Figure 28. Volume Implementation for the DAC1-4 and Low-latency Path
TPS
MODE
DAC5 FLTR[1]
Envelope
Tracking
1
0
1
0
DAC5 Noise
Gate Threshold
0
1
x
DAC5 FLTR[1]
+
Max Detect
Noise Gate
x
TPS
OFFSET
INV. DAC5
Mute & Volume
Transition
DAC5 Volume
Register Setting
-1
-2
0
1
0
1
+
DAC5
Data in
0
1
TPS
Full MODE
Scale
Code
Interpolation
Filter
0
1
Modulator
DAC
AOUT5
DAC5 FLTR[0]
Soft Ramp
+
Master Volume
Register Setting
Limiter
(+6 to -83 dB)
Immediate
Change
1
0
0 dB
0
1
DAC5 ATT
DAC5 MVC
TPS
GAIN
TPS
MODE
0
1
Sample and
Hold
MUTE DAC5
Figure 29. Volume Implementation for the DAC5 Path
4.6.6.1
Mute Behavior
Each DAC channel volume is controlled by the sum (in dB) of the individual channel volume and the master volume registers (except for DAC5 if the DAC5 MVC bit is cleared). The channel and master volume
control registers have a range of +6 dB to -90 dB with a nominal resolution of 6.02/16 dB per each bit, which
is approximately 0.4 dB. For DAC1-4, the sum of the two volume settings is limited to a range of +6 dB to
-90 dB. For DAC5, the sum of the two volume settings is limited to a range of +6 dB to -83 dB. Any volume
setting below these ranges will result in infinite attenuation thus muting the channel.
A DAC channel or low latency path may alternatively be muted by using the mute register bits, power
down bits, or the Noise Gate feature. For any case when the mute engages (volume is less than minimum
limit, power down bit is set, mute bit is set, or Noise Gate is engaged), the CS4234 will mute the channel
immediately or soft-ramp the volume down at a rate specified by the MUTE DELAY[1:0] bits depending
on the settings of the DAC1-4 ATT. and DAC5 ATT. bits in the "DAC Control 3" register. This behavior
also applies when unmuting a channel. The low latency paths are always muted or unmuted immediately.
DS899F1
43
CS4234
4.6.6.2
Soft Ramp
The CS4234 soft ramp feature (enabled using the DAC1-4 ATT. and DAC5 ATT. bits) is activated on mute
and unmute transitions as well as any normal volume register changes. To avoid any potential audible
artifacts due to the soft ramping, the volume control algorithm implements the ramping function differently
based upon how the user attempts to control the volume.
If the user changes the volume in distant discrete steps such as what would happen if a button were
pressed on a user interface to temporarily add attenuation to or mute a channel, then the volume is
ramped from the current setting to the new setting at a constant rate set by the MUTE DELAY[1:0] bits.
Alternatively, if the user controls the volume through a knob or slider interface, a volume envelope is sampled at a slow, not-necessarily uniform rate (typically 1-20 Hz) and sent to the CS4234. In this case the
ramping algorithm detects a short succession of volume changes attempting to track the volume envelope
and dynamically adjusts the soft-ramp rate.
If the CS4234 were to use a constant ramp rate between the volume changes it receives, its output volume
envelope may either lag behind the user-generated envelope if the ramp rate is set too low (possibly not
reaching the peaks and dulling the envelope) or the output volume envelope may cause a stair-case effect
resulting in audible zipper noise if the ramp rate is set too high. By instead adapting the soft-ramp rate to
fit the envelope given by the incoming volume samples, the envelope lag time is limited and the zipper
noise is avoided. In this mode the soft ramp algorithm linearly interpolates the volume between the volume
changes. There is a lag of one volume change sample since two samples are required to calculate the
first ramp rate.
See Figure 30 for the soft ramp diagram. On the first volume sample received, the CS4234 only detects
the possible beginning of a volume envelope sequence and resets an envelope counter. The volume
starts ramping to the new volume setting at a constant rate controlled by the MUTE DELAY[1:0] setting.
If the envelope counter times out before a new volume sample is received, the next received sample is
treated in the same way as the previous sample and the ramp rate is kept constant. In this way, as long
as the volume samples are distant from each other by more than the envelope counter time out, the rate
is kept constant resulting in the soft-ramp behavior described in the button-press example.
However if the next volume sample is received before the envelope counter times out, then it is assumed
to be part of a volume envelope sequence. The envelope counter is reset and as long as new samples
are received in succession before a time out occurs, the sequence is continued. Starting at the second
volume sample of an envelope sequence, the ramp rate is adjusted using the equation shown in
Figure 30.
DS899F1
44
CS4234
Wait State
Envelope Counter
Running
USER: Change
Volume or Mute
Register
Envelope
Counter
Timed Out?
Yes
Reset Envelope
Counter
No
Reset Envelope
Counter
Ramp Rate 
Ramp Rate =
MUTE_DELAY
New Volume Setting - Current Volume Setting
Time Between Volume Changes
MIN_DELAY
Limit Ramp Rate
MAX_DELAY
Figure 30. Soft Ramp Behavior
Two control parameters allow the user to limit the ramp-rate range to achieve optimum effect. The MIN
DELAY[2:0] setting limits the maximum ramp rate; higher values will introduce more lag in the envelope
tracking while providing a smoother ramp. The MAX DELAY[2:0] setting limits the minimum ramp rate;
lower values will permit closer tracking of the envelope but may reintroduce zipper noise. The default values of these registers are recommended as a starting point. It is possible to disable the volume envelope
tracking and always produce a constant ramp rate. To accomplish this, set the MIN DELAY[2:0] and MAX
DELAY[2:0] values to match the MUTE DELAY[1:0] setting.
The envelope counter time out period which defines the boundary between the two soft-ramping behaviors depends on the base rate. It is equal to approximately 100,000/Fs.
The MUTE DELAY[1:0], MIN DELAY[2:0], and MAX DELAY[2:0] bits specify a delay equal to a multiple
of the base period between volume steps of 6.02/64 dB, which is approximately 0.1 dB. This is the internal
resolution of the volume control engine. Consequently the soft-ramp rate can be expressed in ms/dB as
shown in Table 8.
DS899F1
45
CS4234
Fs = 48 kHz or 96 kHz (Base = 48 kHz)
Ramp Rate
Time to Ramp
Time to Ramp
to Full Scale
6 dB (ms)
(ms)
ms/dB
1 x Base
21.33
1.33
0.22
2 x Base
42.67
2.67
4 x Base
85.33
5.33
8 x Base
170.67
16 x Base
341.33
Fs = 32 kHz or 64 kHz (Base = 32 kHz)
Time to Ramp
Time to Ramp
to Full Scale
6 dB (ms)
(ms)
ms/dB
32
2
0.33
0.44
64
4
0.66
0.89
128
8
1.33
10.67
1.77
256
16
2.66
21.33
3.54
512
32
5.32
32 x Base
682.67
42.67
7.09
1024
64
10.63
64 x Base
1365.33
85.33
14.17
2048
128
21.26
128 x Base
2730.67
170.67
28.35
4096
256
42.52
Table 8. Soft Ramp Rates
Full-scale ramp is 96 dB (-90 dB to +6 dB)
4.6.6.3
Noise Gate
The CS4234 is equipped with a Noise Gate feature that mutes the output of a given path if the signal drops
below a given bit depth for 8192 samples. This feature can be independently enabled for any of the three
output paths. While the enabling or disabling of the Noise Gate feature is done by output path, each of the
channels within the paths have separate monitoring circuitry that will trigger the Noise Gate function independently of the other channels. For instance, if the Noise Gate were enabled for a given path and one of
the channels within that given path were to exhibit a pattern of more than 8192 samples of either all “1’s”
or all “0’s”, the output for that particular channel would be muted (and subsequently unmuted), independently of the other channels within the same path. To enable the Noise Gate feature, set the xNG[2:0] bits
to the desired bit depth. The available bit depth settings are shown in Table 9.
xNG[2:0] Setting
Channel is muted after “x” bits
000
Upper 13 Bits (-72 dB)
001
Upper 14 Bits (-78 dB)
010
Upper 15 Bits (-82 dB)
011
Upper 16 Bits (-90 dB)
100
Upper 17 Bits (-94 dB)
101
Upper 18 Bits (-102 dB)
110
Upper 24 Bits (-138 dB)
111
Noise Gate Disabled
Table 9. Noise Gate Bit Depth Settings
When the upper “x” bits, as dictated by the xNG[2:0] settings, are either all “1’s” or all “0’s” for 8192 consecutive samples, the Noise Gate will engage for that channel. Setting all of these bits to ‘111’ will disable
the Noise Gate feature. If the Noise Gate feature engages for the Low-Latency path, the mute event will
occur immediately. If the Noise Gate feature engages for the DAC1-4 or DAC5 path, it will transition into
and out of mute as dictated by the DAC1-4 ATT. and DAC5 ATT. bits in the "DAC Control 3" register.
DS899F1
46
CS4234
4.7
Reset Line
The reset line of the CS4234 is used to place the device into a reset condition. In this condition, all of the
values of the CS4234 control port are set to their default values. This mode of operation is the lowest power
mode of operation for the CS4234 and should be used whenever the device is not operating in order to save
power. During the power up and power down sequence, it is often necessary for the CS4234 devices to be
placed into (and taken out of) reset at a different moment in time than the amplifiers to which they are connected in order to minimize audible clicks and pops during the sequence. For this reason, it is advisable to
run separate reset lines for each type of device, i.e. one reset line for the CS4234 devices and one for the
CS44417 devices.
4.8
Error Reporting and Interrupt Behavior
The CS4234 is equipped with a suite of error reporting and protection. The types of errors that are detected,
the notification method for these errors, and the steps needed to clear the errors are detailed in Table 10.
It is important to note that the interrupt notification bits for all of the errors are triggered on the edge of the
occurrence of the event. They are not level-triggered and therefore do not indicate the presence of an error
in real time. This means that, a “1” in the error’s respective field inside the Interrupt Notification register only
indicates that the error occurred since the last time the register was cleared and not necessarily that the
error is currently occurring.
Outputs muted upon
occurrence?
All PDNx bits must be
set and then cleared to
resume normal
operation?
Disallowed Test Mode Device has entered test mode due
Entry
to an errant I²C write.
(Note 36)
No
No
Serial Port Error
FS/LRCK or SCLK has become
invalid.
Yes
Yes
Clocking Error
The speed mode which the device
is receiving is different than the
speed mode set in the SPEED
MODE[1:0] bits, or the PLL is
unlocked from input signal.
Yes
Yes
ADCx Overflow
ADC inputs are larger than the permitted full scale signal.
No
No
Normal operation continues
but audible distortion occurs.
DACx Clip
DAC output level is larger than the
available rail voltage.
No
No
Normal operation continues
but audible distortion occurs.
Name of Error
Event(s) that caused the error
Table 10. Error Reporting and Interrupt Behavior Details
Note:
36. This error is provided to aid in troubleshooting during software development. Entry into the test mode
of the device may cause permanent damage to the device and should not be done intentionally.
4.8.1
Interrupt Masking
An occurrence of any of the errors mentioned above will cause the interrupt line to engage in order to notify the system controller that an error occurred. If it is preferred that the error not cause the interrupt line
to engage, this error can be masked in its respective mask register. It is important to note that, in the event
of an error, the interrupt notification bit for the respective error will reflect the occurrence of the event, re-
DS899F1
47
CS4234
gardless of the setting of the mask bit. Setting the mask bit only prevents the interrupt pin from being
flagged upon the occurrence.
4.8.2
Interrupt Line Operation
As mentioned previously, the interrupt line of the CS4234 will be pulled low or high (depending on the settings of the “INT PIN[1:0]” bits in the "Interrupt Control" register) after an interrupt condition occurs, provided that the event is not masked in the mask register. If the CS4234’s interrupt line is to be connected
onto a single bus with other devices, it is advisable to use it in the open drain mode of operation. If no
other devices are connected to the interrupt line, it may be used in the CMOS mode of operation. When
used in the open drain configuration, it is necessary to connect a pull-up resistor to this net, which will
ensure a known state on the net when no error is present. Please refer to the typical connection diagram
for the appropriate pull-up resistor value.
4.8.3
Error Reporting and Clearing
In the event of an error, the interrupt line will be engaged - provided the mask bit for that error is not set.
When the interrupt notification registers are read to determine the source of the error, the mask bit for
whichever error occurred will be set automatically by the CS4234. The system controller should begin to
take corrective action to clear the error. Once the error has been cleared, the system controller should
clear the mask bit in the appropriate mask register to ensure that a subsequent occurrence of the error
will cause the interrupt line to engage appropriately. This behavior is detailed in Figure 31 on page 49.
DS899F1
48
CS4234
USER: Mask bit(s)
set to 0
New Unmasked Error
New Unmasked Error
New Unmasked Error
New Unmasked Error
New Unmasked Error
New Unmasked Error
Unmasked error
occurs
Status Register bit
changes to ‘1’ and
INT pin set to
active level
USER: Read
Status Registers
(see status bit(s) =
‘1’)
Mask bit(s) of
corresponding
status bit(s) set to
‘1’
INT pin set to
inactive level
Status Register
bit(s) set to ‘1’
USER: Takes
Corrective Action
All Status Register
bits cleared
Are any
errors still
occurring?
Yes
No
USER: Read
Status Registers
(see all status bits
= ‘0’)
Figure 31. Interrupt Behavior and Example Interrupt Service Routine
DS899F1
49
CS4234
5. REGISTER QUICK REFERENCE
Default values are shown below the bit names.
AD
Function
7
6
5
4
3
2
1
0
1
0
0
0
0
0
0
0
(Read Only Bits are shown in Italics)
01h
p 52
02h
p 52
03h
p 52
04h
05h
p 52
06h
p 53
07h
p 54
08h
Device ID
A and B
Device ID
C and D
Device ID
E and F
Variant ID
Revision ID
Clock and
SP Sel.
Sample
Width Sel.
SP Control
p 55
09h
p 56
0Ah
p 57
0Bh
p 57
0Ch
p 58
0Dh
p 58
0Eh
p 59
0Fh
p 60
10h
p 61
11h
p 61
12h
p 62
13h
p 63
14h
p 63
15h
p 64
SP Data
Sel.
SDIN1
Mask 1
SDIN1
Mask 2
SDIN2
Mask 1
SDIN2
Mask 2
TPS
Control
ADC
Control 1
ADC
Control 2
Low Lat.
Control 1
DAC
Control 1
DAC
Control 2
DEV. ID A[3:0]
0
1
0
0
DEV. ID B[3:0]
0
0
0
0
1
0
1
DEV. ID C[3:0]
DEV. ID D[3:0]
1
DEV. ID E[3:0]
0
0
DEV. ID F[3:0]
0
0
0
0
Reserved [3:0]
0
0
Reserved [3:0]
0
0
0
ALPHA REV. ID[3:0]
x
x
x
x
BASE RATE[1:0]
SPEED MODE[1:0]
0
0
0
SDOUTx SW[1:0]
1
INV SCLK
0
INPUT SW[1:0]
1
1
0
1
Reserved
1
0
0
0
x
x
1
1
1
SP FORMAT[1:0]
0
0
x
MCLK RATE[2:0]
0
1
0
DAC1-4 SOURCE[2:0]
0
x
Reserved
0
LOW LAT. SW[1:0]
DAC5 SOURCE[2:0]
Reserved
0
NUMERIC REV. ID[3:0]
0
DAC5 SW[1:0]
1
1
SDO CHAIN
MASTER/
SLAVE
0
0
LL SOURCE[2:0]
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
SDIN1 MASK 1[7:0]
1
1
1
1
1
SDIN1 MASK 2[7:0]
1
1
1
1
1
SDIN2 MASK 1[7:0]
1
1
1
1
1
SDIN2 MASK 2[7:0]
1
1
TPS MODE
0
Reserved
1
1
1
TPS OFFSET[2:0]
0
Reserved
GROUP DELAY[3:0]
0
0
0
0
0
0
VA_SEL
ENABLE
HPF
INV. ADC4
INV. ADC3
INV. ADC2
INV. ADC1
1
1
0
0
0
0
0
0
MUTE
ADC4
MUTE
ADC3
MUTE
ADC2
MUTE
ADC1
PDN
ADC4
PDN
ADC3
PDN
ADC2
PDN
ADC1
1
1
1
LL NG[2:0]
1
1
1
DAC1-4 NG[2:0]
1
1
1
DAC5 NG[2:0]
1
1
1
1
1
Reserved
INV. LL 4
INV. LL 3
INV. LL 2
INV. LL 1
0
0
0
0
0
DAC1-4 DE
DAC5 DE
DAC5 MVC
DAC5 CFG & FLTR[1:0]
0
0
0
0
0
INV. DAC5
INV. DAC4
INV. DAC3
INV. DAC2
INV. DAC1
1
1
1
0
0
0
0
0
DAC
Control 3
DAC5 ATT.
DAC1-4
ATT.
MUTE LL
MUTE DAC5
MUTE DAC4
MUTE DAC3
MUTE DAC2
MUTE DAC1
1
0
1
1
1
1
1
1
DAC
Control 4
VQ RAMP
TPS GAIN
Reserved
PDN DAC5
PDN DAC4
PDN DAC3
PDN DAC2
PDN DAC1
0
0
0
1
1
1
1
1
DS899F1
50
CS4234
AD
Function
7
6
5
4
3
2
1
0
(Read Only Bits are shown in Italics)
16h
p 65
17h
p 66
18h
p 66
19h
p 66
1Ah
p 66
1Bh
p 66
1Ch
p 66
1Dh
Volume
Mode
Master
Volume
DAC1
Volume
DAC2
Volume
DAC3
Volume
DAC4
Volume
DAC5
Volume
MUTE DELAY[1:0]
1
p 66
1Fh
Interrupt
Control
Interrupt
Mask 1
p 68
21h
p 68
22h
p 69
Interrupt
Mask 2
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DAC1 VOLUME[7:0]
1
0
DAC2 VOLUME[7:0]
0
0
0
1
0
DAC3 VOLUME[7:0]
0
0
0
1
0
DAC4 VOLUME[7:0]
0
0
0
0
0
0
1
0
DAC5 VOLUME[7:0]
1
0
0
Reserved[3:0]
Reserved
p 67
20h
0
MAX DELAY[2:0]
MASTER VOLUME[7:0]
1
1Eh
MIN DELAY[2:0]
0
INT MODE
1
INT PIN[1:0]
Reserved[3:0]
1
1
0
1
0
Reserved
Reserved
Reserved
Reserved
Reserved
0
1
0
MASK
TST MODE
ERR
MASK
SP ERR
MASK
CLK ERR
0
0
0
1
0
0
0
0
Reserved
MASK
DAC5 CLIP
MASK
DAC4 CLIP
MASK
DAC3 CLIP
MASK
DAC2 CLIP
MASK
DAC1 CLIP
Reserved
Reserved
0
0
0
0
0
Reserved
MASK
ADC4 OVFL
MASK
ADC3 OVFL
MASK
ADC2 OVFL
MASK
ADC1 OVFL
0
0
1
0
0
0
0
0
Interrupt
Notification 1
TST MODE
SP ERR
CLK MOD ERR
Reserved
ADC4 OVFL
ADC3 OVFL
ADC2 OVFL
ADC1 OVFL
x
x
x
x
x
x
x
x
Interrupt
Notification 2
Reserved
Reserved
Reserved
DAC5 CLIP
DAC4 CLIP
DAC3 CLIP
DAC2 CLIP
DAC1 CLIP
x
x
x
x
x
x
x
x
DS899F1
51
CS4234
6. REGISTER DESCRIPTIONS
All registers are read/write unless otherwise stated. All “Reserved” bits must maintain their default state. Default
values are shaded.
6.1
Device I.D. A and B (Address 01h) (Read Only)
Device I.D. C and D (Address 02h) (Read Only)
Device I.D. E and F (Address 03h) (Read Only)
7
6
5
4
3
2
DEV. ID A[3:0]
7
6
5
4
3
2
DEV. ID C[3:0]
7
6
0
1
0
1
0
DEV. ID D[3:0]
5
4
3
2
DEV. ID E[3:0]
6.1.1
1
DEV. ID B[3:0]
DEV. ID F[3:0]
Device I.D. (Read Only)
Device I.D. code for the CS4234. Example:.
6.2
DEV. ID A[3:0]
DEV. ID B[3:0]
DEV. ID C[3:0]
DEV. ID D[3:0]
DEV. ID E[3:0]
DEV. ID F[3:0]
Part Number
4h
2h
3h
4h
0h
0h
CS4234
Revision I.D. (Address 05h) (Read Only)
7
6
5
4
3
2
1
0
AREVID3
AREVID2
AREVID1
AREVID0
NREVID3
NREVID2
NREVID1
NREVID0
6.2.1
Alpha Revision (Read Only)
CS4234 Alpha (silicon) revision level.
6.2.2
AREVID[3:0]
Alpha Revision Level
Ah
A
...
...
Numeric Revision (Read Only)
CS4234 Numeric (metal) revision level.
NREVID[3:0]
Numeric Revision Level
0h
0
...
...
Note: The Alpha and Numeric revision I.D. are used to form the complete device revision I.D. Example:
A0, A1, B0, B1, B2, etc.
DS899F1
52
CS4234
6.3
Clock and SP Select (Address 06h)
7
6
BASE RATE[1:0]
6.3.1
5
4
SPEED MODE[1:0]
3
2
MCLK RATE[2:0]
1
0
Reserved
Base Rate Advisory
Advises the CS4234 of the base rate of the incoming base rate. This allows for the de-emphasis filters to
be adjusted appropriately and the group delay block for the DAC1-4 path to be calculated correctly. The
CS4234 includes on-chip digital de-emphasis for 32, 44.1, and 48 kHz base rates. It is not supported for
96 kHz or for any settings in Double Speed Mode.
6.3.2
BASE RATE
Base Rate is:
00
48 kHz
01
44.1 kHz
10
32 kHz
11
Reserved
Speed Mode
Sets the speed mode in which the CS4234 will operate.
SPEED MODE
6.3.3
Speed Mode is:
00
Single Speed Mode
01
Double Speed Mode
10
Reserved
11
Auto Detect
Master Clock Rate
Sets the rate at which the master clock is entering the CS4234. Settings are given in “x” multiplied by the
incoming sample rate, as MCLK must scale directly with incoming sample rate.
DS899F1
MCLK RATE
MCLK is:
000
256xFS in Single Speed Mode or 128xFS in Double Speed Mode
001
384xFS in Single Speed Mode or 192xFS in Double Speed Mode
010
512xFS in Single Speed Mode or 256xFS in Double Speed Modex
011
Reserved
100
Reserved
101
Reserved
110
Reserved
111
Reserved
53
CS4234
6.4
Sample Width Select (Address 07h)
7
6
SDOUTx SW[1:0]
6.4.1
5
4
INPUT SW[1:0]
3
2
LOW LAT. SW[1:0]
1
0
DAC5 SW[1:0]
Output Sample Width
These bits set the width of the samples placed into the outgoing SDOUTx streams.
OUTPUT SW
Sample Width is:
00
16 bits
01
18 bits
10
20 bits
11
24 bits
Note: Bits which are wider than the Output Sample Width setting above will be set to zero within the
SDOUTx data stream.
6.4.2
Input Sample Width
These bits set the width of the samples coming into the CS4234 through the SDINx TDM streams.
6.4.3
INPUT SW
Sample Width is:
00
16 bits
01
18 bits
10
20 bits
11
24 bits
Low-Latency Path Sample Width
These bits set the width of the samples which have been placed into the low latency path of the CS4234.
6.4.4
LOW LAT. SW
Sample Width is:
00
16 bits
01
18 bits
10
20 bits
11
24 bits
DAC5 Sample Width
These bits set the width of the samples which have been placed into the DAC5 path of the CS4234.
DS899F1
DAC5 SW
Sample Width is:
00
16 bits
01
18 bits
10
20 bits
11
24 bits
54
CS4234
6.5
Serial Port Control (Address 08h)
7
INV SCLK
6.5.1
6
5
DAC5 SOURCE[2:0]
4
3
2
SP FORMAT[1:0]
1
0
SDO CHAIN MASTER/SLAVE
Invert SCLK
When set, this bit inverts the polarity of the SCLK signal.
6.5.2
INV SCLK
SCLK is:
0
Not Inverted
1
Inverted
DAC5 Input Source
Sets which portion of data is to be routed to the DAC5 data path.
6.5.3
DAC5 SOURCE
Data is routed into the DAC5 path from:
000
LSB’s of slots 1-3 of the TDM stream on SDIN1
001
LSB’s of slots 5-7 of the TDM stream on SDIN1
010
LSB’s of slots 9-11 of the TDM stream on SDIN1
011
LSB’s of slots 13-15 of the TDM stream on SDIN1
100
Mask bits are used to determine the input signal in the DAC5 path. See Section 4.6.5 for details.
101
Reserved
110
Reserved
111
Reserved
Serial Port Format
Sets the format of both the incoming serial data signals and outgoing serial data signal.
6.5.4
SP FORMAT
Format is:
00
Left Justified
01
I2 S
10
TDM (Slave Mode Only)
11
Reserved
Serial Data Output Sidechain
Setting this bit enables the SDOUT1 side chain feature. In this mode, the samples from multiple devices
can be coded into one TDM stream. See Section 4.6.2 ADC Path for more details.
SDO CHAIN
6.5.5
Sidechain is:
0
Disabled
1
Enabled
Master / Slave
Setting this bit places the CS4234 in master mode, clearing it places it in slave.
MASTER / SLAVE CS4234 is in:
0
Slave Mode
1
Master Mode
I²S and Left Justified are the only available serial port formats if the CS4234 is placed into Master Mode.
DS899F1
55
CS4234
6.6
Serial Port Data Select (Address 09h)
7
Reserved
6.6.1
6
Reserved
5
4
DAC1-4 SOURCE[2:0]
3
2
1
LL SOURCE[2:0]
0
DAC1-4 Data Source
Sets which portion of data is to be routed to the DAC1-4 data paths.
DAC1-4 SOURCE Data is routed into the DAC1-4 path from:
6.6.2
000
Slots 1-4 of the TDM stream on SDIN1
001
Slots 5-8 of the TDM stream on SDIN1
010
Slots 9-12 of the TDM stream on SDIN1
011
Slots 13-16 of the TDM stream on SDIN1
100
Slots 1-4 of the TDM stream on SDIN2
101
Slots 5-8 of the TDM stream on SDIN2
110
Slots 9-12 of the TDM stream on SDIN2
111
Slots 13-16 of the TDM stream on SDIN2
Low-latency Path Source
Sets which portion of data is to be routed to the Low-Latency data path.
DS899F1
LL SOURCE
Data is routed into the Low Latency path from:
000
Slots 1-4 of the TDM stream on SDIN1
001
Slots 5-8 of the TDM stream on SDIN1
010
Slots 9-12 of the TDM stream on SDIN1
011
Slots 13-16 of the TDM stream on SDIN1
100
Slots 1-4 of the TDM stream on SDIN2
101
Slots 5-8 of the TDM stream on SDIN2
110
Slots 9-12 of the TDM stream on SDIN2
111
Slots 13-16 of the TDM stream on SDIN2
56
CS4234
6.7
Serial Data Input 1 Mask 1 (Address 0Ah)
7
6
6.7.1
5
4
3
SDIN1 MASK 1[7:0]
2
1
0
SDIN1 Mask 1
This field determines what data is masked from the max detect and envelope tracking blocks in the DAC5
data path.
6.8
SDIN1 MASK 1
Unmasked Data (in addition to any other data that is unmasked by its respective mask bits):
11111111
All Data is Masked.
0xxxxxxx
Slot 1 of SDIN1.
x0xxxxxx
Slot 2 of SDIN1.
xx0xxxxx
Slot 3 of SDIN1.
xxx0xxxx
Slot 4 of SDIN1.
xxxx0xxx
Slot 5 of SDIN1.
xxxxx0xx
Slot 6 of SDIN1.
xxxxxx0x
Slot 7 of SDIN1.
xxxxxxx0
Slot 8 of SDIN1.
Serial Data Input 1 Mask 2 (Address 0Bh)
7
6.8.1
6
5
4
3
SDIN1 MASK 2[7:0]
2
1
0
SDIN1 Mask 2
This field determines what data is masked from the max detect and envelope tracking blocks in the DAC5
data path.
DS899F1
SDIN1 MASK 2
Unmasked Data (in addition to whatever other data is unmasked by its respective mask bits):
11111111
All Data is masked.
0xxxxxxx
Slot 9 of SDIN1.
x0xxxxxx
Slot 10 of SDIN1.
xx0xxxxx
Slot 11 of SDIN1.
xxx0xxxx
Slot 12 of SDIN1.
xxxx0xxx
Slot 13 of SDIN1.
xxxxx0xx
Slot 14 of SDIN1.
xxxxxx0x
Slot 15 of SDIN1.
xxxxxxx0
Slot 16 of SDIN1.
57
CS4234
6.9
Serial Data Input 2 Mask 1 (Address 0Ch)
7
6
6.9.1
5
4
3
SDIN2 MASK 1[7:0]
2
1
0
SDIN2 Mask 1
This field determines what data is masked from the max detect and envelope tracking blocks in the DAC5
data path.
6.10
SDIN2 MASK 1
Unmasked Data (in addition to any other data that is unmasked by its respective mask bits):
11111111
All Data is Masked.
0xxxxxxx
Slot 1 of SDIN2.
x0xxxxxx
Slot 2 of SDIN2.
xx0xxxxx
Slot 3 of SDIN2.
xxx0xxxx
Slot 4 of SDIN2.
xxxx0xxx
Slot 5 of SDIN2.
xxxxx0xx
Slot 6 of SDIN2.
xxxxxx0x
Slot 7 of SDIN2.
xxxxxxx0
Slot 8 of SDIN2.
Serial Data Input 2 Mask 2 (Address 0Dh)
7
6
5
4
3
SDIN2 MASK 2[7:0]
2
1
0
6.10.1 SDIN2 Mask 2
This field determines what data is masked from the max detect and envelope tracking blocks in the DAC5
data path.
DS899F1
SDIN2 MASK 2
Unmasked Data (in addition to whatever other data is unmasked by its respective mask bits):
11111111
All Data is masked.
0xxxxxxx
Slot 9 of SDIN2.
x0xxxxxx
Slot 10 of SDIN2.
xx0xxxxx
Slot 11 of SDIN2.
xxx0xxxx
Slot 12 of SDIN2.
xxxx0xxx
Slot 13 of SDIN2.
xxxxx0xx
Slot 14 of SDIN2.
xxxxxx0x
Slot 15 of SDIN2.
xxxxxxx0
Slot 16 of SDIN2.
58
CS4234
6.11
Tracking Power Supply Control (Address 0Eh)
7
TPS MODE
6.11.1
6
5
TPS OFFSET[2:0]
4
3
2
1
GROUP DELAY[3:0]
0
Tracking Power Supply Mode
If DAC5 FLTR (Section 6.15.5) is set to Tracking Power Supply Mode, setting this bit changes the reference of the DAC5 output from 0 V to full-scale output voltage. This feature is used when the topology of
the power supply decreases output signal as the reference signal is increased, and increases its output
signal when the reference signal is decreased. If DAC5 FLTR is not set to Tracking Power Supply Mode,
setting this bit inverts the DAC5 output.
6.11.2
TPS MODE
Output of DAC5 is referenced to:
0
0 VDREGC
1
Full Scale
Tracking Power Supply Offset
Determines the DC offset is added to the DAC5 output. The DC offset value changes proportionally to VA
changes. Note when TPS Mode = 1 and TPS Gain = 1, the DC offset amount is double the values listed
in the table.
TPS OFFSET
DS899F1
DC Offset on DAC5 output [% of Full Scale]:
000
0
001
3
010
6
011
9
100
12
101
15
110
18
111
21
59
CS4234
6.11.3
Group Delay
Sets the group delay added to the DAC1-4 path. This delay is in addition to any inherent delay in the DAC.
Modify these bits only while all of the ADCs and DACs are powered down and the DACs are in mute state.
GROUP
DELAY
[3:0]
Nominal
Group
Delay [s]
Sample Rate
Sample Rate
Sample Rate
Sample Rate
Sample Rate
Sample Rate
32 kHz
44.1 kHz
48 kHz
64 kHz
88.2 kHz
96 kHz
# of
# of
# of
# of
# of
# of
Delay [s]
Delay [s]
Delay [s]
Delay [s]
Delay [s]
Delay [s]
Samples
Samples
Samples
Samples
Samples
Samples
0000
0
0
0
0
0
0
0
0
0
0
0
0
0
0001
100
3
94
4
91
5
104
6
94
9
102
10
104
0010
150
5
156
7
159
7
146
10
156
13
147
14
146
0011
200
6
188
9
204
10
208
13
203
18
204
19
198
0100
225
7
219
10
227
11
229
14
219
20
227
22
229
0101
250
8
250
11
249
12
250
16
250
22
249
24
250
0110
275
9
281
12
272
13
271
18
281
24
272
26
271
0111
300
10
312
13
295
14
292
19
297
27
306
29
302
1000
325
10
312
14
317
15
312
21
328
29
329
31
323
1001
350
11
344
15
340
17
354
22
344
31
351
34
354
1010
375
12
375
16
363
18
375
24
375
33
374
36
375
1011
400
13
406
17
386
19
396
26
406
36
408
38
396
1100
425
14
438
18
408
20
417
27
422
38
431
41
427
1101
450
15
469
20
454
21
438
29
453
40
454
43
448
1110
475
15
469
21
476
23
479
30
469
42
476
46
479
1111
500
16
500
22
499
24
500
32
500
44
499
48
500
6.12
ADC Control 1 (Address 0Fh)
7
Reserved
6
Reserved
5
4
3
2
1
0
VA_SEL
ENABLE HPF
INV. ADC4
INV. ADC3
INV. ADC2
INV. ADC1
6.12.1 VA Select
Scales internal operational voltages appropriately for VA level. This bit must be set appropriately for the
VA voltage level used in the application to ensure proper operation and performance of the device.
VA_SEL
Must be set when VA is:
0
3.3 VDC
1
5 VDC
6.12.2 Enable High-Pass Filter
Enables high-pass filter for the ADC path.
ENABLE HPF
High Pass Filter is:
0
Disabled
1
Enabled
6.12.3 Invert ADCx
Inverts the polarity of the ADCx signal.
INV. ADCx
DS899F1
ADCx Polarity is:
0
Not Inverted
1
Inverted
60
CS4234
6.13
ADC Control 2 (Address 10h)
7
MUTE ADC4
6
MUTE ADC3
5
MUTE_ADC2
4
MUTE ADC1
3
PDN ADC4
2
PDN ADC3
1
PDN ADC2
0
PDN ADC1
2
INV. LL3
1
INV. LL2
0
INV. LL1
6.13.1 Mute ADCx
Mutes the ADCx signal
MUTE ADCx
ADC is:
0
Not Muted
1
Muted
6.13.2 Power Down ADCx
Powers down the ADCx path.
6.14
PDN ADCx
ADC is:
0
Powered Up
1
Powered Down
Low Latency Path Control (Address 11h)
7
6
LL NG[2:0]
5
4
Reserved
3
INV. LL4
6.14.1 Low Latency Noise Gate
This sets the bit depth at which the Noise Gate feature should engage for the low-latency path.
LL NG[2:0]
Noise Gate is set at: [b]
000
Upper 13 Bits (72 dB)
001
Upper 14 Bits (78 dB)
010
Upper 15 Bits (84 dB)
011
Upper 16 Bits (90 dB)
100
Upper 17 Bits (96 dB)
101
Upper 18 Bits (102 dB)
110
Upper 24 Bits (138 dB)
111
Noise Gate Disabled
6.14.2 Invert Low Latency Channel x
Inverts the polarity of the data entering into the low-latency channel.
INV. LLx
DS899F1
Low Latency Data is:
0
Not Inverted
1
INverted
61
CS4234
6.15
DAC Control 1 (Address 12h)
7
6
DAC1-4 NG
5
4
DAC1-4 DE
3
DAC5 DE
2
DAC5 MVC
1
0
DAC5 CFG & FLTR[1:0]
6.15.1 DAC1-4 Noise Gate
This sets the bit depth at which the Noise Gate feature should engage for the DAC1-4 path.
DAC1-4 NG[2:0]
Noise Gate is set at: [b]
000
Upper 13 Bits (72 dB)
001
Upper 14 Bits (78 dB)
010
Upper 15 Bits (84 dB)
011
Upper 16 Bits (90 dB)
100
Upper 17 Bits (96 dB)
101
Upper 18 Bits (102 dB)
110
Upper 24 Bits (138 dB)
111
Noise Gate Disabled
6.15.2 DAC1-4 De-emphasis
Enables or disables de-emphasis for the DAC1-4 path. See Section 4.6.3.1 for details. The CS4234 includes on-chip digital de-emphasis for 32, 44.1, and 48 kHz base rates. It is not supported for 96 kHz or
for any settings in Double-Speed Mode.
DAC1-4 DE
De-emphasis is:
0
Disabled
1
Enabled
6.15.3 DAC5 De-emphasis
Enables or disables de-emphasis for the DAC5 path. See Section 4.6.5.4 for details. The CS4234 includes on-chip digital de-emphasis for 32, 44.1, and 48 kHz sample rates. It is not supported for 96 kHz
or for any settings in Double-speed Mode.
DAC5 DE
De-emphasis is:
0
Disabled
1
Enabled
6.15.4 DAC5 Master Volume Controlled
Selects whether the DAC5 data path is subject to or independent of the master volume control.
DAC5 MVC
DS899F1
DAC5 volume is:
0
Not subject to the master volume control
1
Subject to the master volume control.
62
CS4234
6.15.5 DAC5 Configuration and Filter Selection
Selects the filtering applied to the DAC5 data or configures the DAC5 Path used to generate a tracking
power supply reference. If placed into Tracking Power Supply mode, an interpolation filter is applied to
the outgoing data; otherwise, either an interpolation or a sample-and-hold filter can be applied to the path.
6.16
DAC5 FLTR
Filter Selected is:
00
Interpolation Filter
01
Sample and Hold
10
Tracking Power Supply Mode (See Section 4.6.5.1 for details)
11
Reserved
DAC Control 2 (Address 13h)
7
6
DAC5 NG[2:0]
5
4
INV. DAC5
3
INV. DAC4
2
INV. DAC3
1
INV. DAC2
0
INV. DAC1
6.16.1 DAC5 Noise Gate
This sets the bit depth at which the Noise Gate feature should engage for the DAC5 path.
DAC5 NG
Noise Gate is set at: [b]
000
Upper 13 Bits (72 dB)
001
Upper 14 Bits (78 dB)
010
Upper 15 Bits (84 dB)
011
Upper 16 Bits (90 dB)
100
Upper 17 Bits (96 dB)
101
Upper 18 Bits (102 dB)
110
Upper 24 Bits (138 dB)
111
Noise Gate Disabled
6.16.2 Inv. DACx
Inverts the polarity of the DACx signal.
INV. DACx
DACx Polarity is:
0
Not Inverted
1
Inverted
When the DAC5 path is put into TPS mode, the invert bit for the DAC5 path will be inoperable.
6.17
DAC Control 3 (Address 14h)
7
DAC5 ATT
6
DAC1-4 ATT
5
MUTE LL
4
MUTE DAC5
3
MUTE DAC4
2
MUTE DAC3
1
MUTE DAC2
0
MUTE DAC1
6.17.1 DAC5 Attenuation
Sets the mode of attenuation used for the DAC5 path.
DAC5 ATT
Attenuation events happen:
0
On a soft ramp
1
Immediately
Note:
DS899F1
See Section 4.6.6 Volume Control for details regarding the attenuation modes.
63
CS4234
6.17.2 DAC1-4 Attenuation
Sets the mode of attenuation used for the DAC1-4 path.
DAC1-4 ATT
Attenuation events happen:
0
On a soft ramp
1
Immediately
Note:
See Section 4.6.6 Volume Control for details regarding the attenuation modes.
6.17.3 Mute Low-latency Path
Mutes the low-latency path.
MUTE LL
Low latency path is:
0
Not Muted
1
Muted
6.17.4 Mute DACx
Mutes the DACx signal.
6.18
MUTE DACx
DACx is:
0
Not Muted
1
Muted
DAC Control 4 (Address 15h)
7
VQ RAMP
6
TPS GAIN
5
Reserved
4
PDN DAC5
3
PDN DAC4
2
PDN DAC3
1
PDN DAC2
0
PDN DAC1
6.18.1 VQ Ramp
Ramps common mode voltage “VQ” down to ground. This bit needs to be set before asserting reset pin.
VQ RAMP
Effect:
0
VQ is set at nominal level (VA/2)
1
VQ is ramped from nominal level to ground.
6.18.2 TPS Mode 1 Gain Select
When “TPS MODE” bit in the "TPS Control" register is set to 1, this bit sets the gain of the signal through
the TPS path.
TPS GAIN
Effect:
0
Gain is 1
1
Gain is 2
6.18.3 Power Down DACx
Powers down the DACx path.
DS899F1
PDN DACx
DACx is:
0
Powered Up
1
Powered Down
64
CS4234
6.19
Volume Mode (Address 16h)
7
6
MUTE DELAY[1:0]
5
4
MIN DELAY[2:0]
3
2
1
MAX DELAY[2:0]
0
6.19.1 Mute Delay
Sets the delay between the volume steps during the muting and unmuting of a signal when the attenuation
mode is set to soft ramp. Each step of the ramp is equal to 6.02/64 dB ~= 0.094 dB. Settings are given as
“x” times the base period.
MUTE DELAY
Delay is:
00
1x
01
4x
10
16x
11
64x
6.19.2 Minimum Delay
Sets the minimum delay before each volume transition. Settings are given in “x” times the base period.
See Section 4.6.6 Volume Control for more details regarding the operation of the volume control.
MIN DELAY
Minimum Delay is:
000
1x
001
2x
010
4x
011
8x
100
16x
101
32x
110
64x
111
128x
6.19.3 Maximum Delay
Sets the maximum delay before the volume transition. Settings are given in “x” times the base period. See
Section 4.6.6 Volume Control for more details regarding the operation of the volume control.
DS899F1
MAX DELAY
Maximum Delay is:
000
1x
001
2x
010
4x
011
8x
100
16x
101
32x
110
64x
111
128x
65
CS4234
6.20
Master and DAC1-5 Volume Control (Address 17h, 18h, 19h, 1Ah, 1Bh, and 1Ch)
7
6
5
4
3
x VOLUME[7:0]
2
1
0
6.20.1 x Volume Control
Sets the level of the x Volume Control. Each volume step equals 6.02/16 dB ~= 0.38 dB. See Section
4.6.6.1 on page 43 for the muting behavior of these volume registers.
6.21
x VOLUME
x Volume is: [dB]
00000000
+6.02
00001111
+0.38
00010000
0
00010001
-0.38
00011000
-3.01
...
...
11101100
-82.78 (most total attenuation before mute for DAC5)
11101101
-83.15 (least total attenuation before unmute for DAC5)
...
...
11111110
-89.55 (most total attenuation before mute for DAC1-4)
11111111
-89.92 (least total attenuation before unmute for DAC1-4)
Interrupt Control (Address 1Eh)
7
INT MODE
6
5
INT POL [1:0]
4
Reserved
3
Reserved
2
Reserved
1
Reserved
0
Reserved
6.21.1 INT MODE
Sets the behavior mode of the interrupt registers of the device. In the default configuration, if the interrupt
notification registers are read and any error is found to have occurred since the last clearing of that register, the device will automatically set the corresponding mask bit in the appropriate mask register. In the
nondefault configuration, the mask bits will not be set automatically.
INT MODE
Upon the reading of an error out of the interrupt notification bits, the CS4234 will:
0
Automatically set the corresponding mask bit.
1
Not set the corresponding mask bit.
6.21.2 Interrupt Pin Polarity
Sets the output mode of the interrupt pin.
INT POL
DS899F1
Output mode of the interrupt pin is:
00
Active High
01
Active Low
10
Active Low/Open Drain
11
Reserved
66
CS4234
6.22
Interrupt Mask 1 (Address 1Fh)
7
MASK
TST MODE ERR
6
MASK
SP ERR
5
MASK
CLK ERR
4
Reserved
3
MASK
ADC4 OVFL
2
MASK
ADC3 OVFL
1
MASK
ADC2 OVFL
0
MASK
ADC1 OVFL
6.22.1 Test Mode Error Interrupt Mask
Allows or prevents a Test Mode Error event from flagging the interrupt pin. A test mode error occurs when
an inadvertent I²C write places the device in test mode.
MASK
TST MODE ERR
In the event of a Test Mode Error event, Interrupt Pin will:
0
Be Flagged
1
Not be flagged
6.22.2 Serial Port Error Interrupt Mask
Allows or prevents a Serial Port Error event from flagging the interrupt pin. A serial port error occurs when
any of the following control port parameters are changed without first placing the device into power down
(power down is defined as all Power Down ADCx and Power Down DACx bits are set to 1):
•
Serial Port Format: SP FORMAT[1:0]
•
Speed Mode: SPEED MODE[1:0] (If the MCLK/FS ratio changes without the device being powered
down, it will flag this error as well as the Clocking Error.)
MASK
SP ERR
In the event of a Serial Port Error event, Interrupt Pin will:
0
Be Flagged
1
Not be flagged
6.22.3 Clocking Error Interrupt Mask
Allows or prevents a Clocking Error event from flagging the interrupt pin. See Section 4.8 for details.
MASK
CLK ERR
In the event of a Clocking Error event, Interrupt Pin will:
0
Be Flagged
1
Not be flagged
6.22.4 ADCx Overflow Interrupt Mask
Allows or prevents an ADCx Overflow event from flagging the interrupt pin.
DS899F1
MASK
ADCx OVFL
In the event of an ADCx Overflow event, Interrupt Pin will:
0
Be Flagged
1
Not be flagged
67
CS4234
6.23
Interrupt Mask 2 (Address 20h)
7
6
Reserved
Reserved
5
4
3
2
1
0
Reserved
MASK
DAC5 CLIP
MASK
DAC4 CLIP
MASK
DAC3 CLIP
MASK
DAC2 CLIP
MASK
DAC1 CLIP
6.23.1 DACx Clip Interrupt Mask
Allows or prevents a DACx Clip event from flagging the interrupt pin.
MASK
DACx CLIP
6.24
In the event of a DACx Clip event, Interrupt Pin will:
0
Be Flagged
1
Not be flagged
Interrupt Notification 1 (Address 21h) (Read Only)
7
TST MOD ERR
6
SP ERR
5
CLK ERR
4
Reserved
3
ADC4 OVFL
2
ADC3 OVFL
1
ADC2 OVFL
0
ADC1 OVFL
6.24.1 Test Mode Error
A Test Mode Error occurred since the last clearing of the Interrupt Notification register.
TST MOD ERR
Since the last clearing of the Interrupt Notification Register, a Test Mode Error:
0
Has Not Occurred
1
Has Occurred
6.24.2 Serial Port Error
A Serial Port Error occurred since the last clearing of the Interrupt Notification register.
SP ERR
Since the last clearing of the Interrupt Notification Register, a Serial Port Error:
0
Has Not Occurred
1
Has Occurred
6.24.3 Clocking Error
A Clocking Error occurred since the last clearing of the Interrupt Notification register.
CLK ERR
Since the last clearing of the Interrupt Notification Register, a Clocking Error:
0
Has Not Occurred
1
Has Occurred
6.24.4 ADCx Overflow
An ADCx Overflow occurred since the last clearing of the Interrupt Notification register.
DS899F1
ADCx OVFL
Since the last clearing of the Interrupt Notification Register, an ADCx Overflow Error:
0
Has Not Occurred
1
Has Occurred
68
CS4234
6.25
Interrupt Notification 2 (Address 22h) (Read Only)
7
6
5
4
3
2
1
0
Reserved
Reserved
Reserved
DAC5 CLIP
DAC4 CLIP
DAC3 CLIP
DAC2 CLIP
DAC1 CLIP
6.25.1 DACx Clip
A DACx Clip occurred since the last clearing of the Interrupt Notification register.
DACx CLIP
DS899F1
Since the last clearing of the Interrupt Notification Register, a DACx Clip Error:
0
Has Not Occurred
1
Has Occurred
69
CS4234
7. ADC FILTER PLOTS
Transition Band
0
−10
−10
−20
−20
−30
−30
−40
−40
Amplitude (dB)
Amplitude (dB)
Stopband Rejection
0
−50
−50
−60
−60
−70
−70
−80
−80
−90
−90
−100
0
0.1
0.2
0.3
0.4
0.5
0.6
Frequency (normalized to Fs)
0.7
0.8
0.9
−100
0.4
1
0.42
Figure 32. ADC Stopband Rejection
0.44
0.46
0.48
0.5
0.52
Frequency (normalized to Fs)
−1
0.04
−2
0.03
−3
0.02
−4
0.01
Amplitude (dB)
Amplitude (dB)
0.05
−5
−0.01
−7
−0.02
−8
−0.03
−9
−0.04
0.47
0.48
0.49
0.5
0.51
Frequency (normalized to Fs)
0.52
0.53
0.54
0.55
−0.05
0
0.05
Figure 34. ADC Transition Band (Detail)
0.1
0.15
−0.5
−1
−1
Amplitude (dB)
Amplitude (dB)
−0.5
−1.5
−2
−2.5
−2.5
4
6
8
10
Frequency (Hz)
12
14
16
Figure 36. ADC HPF (48 kHz)
DS899F1
0.4
0.45
0.5
−1.5
−2
2
0.35
High−Pass Filter Response (Fs = 96kHz)
0
0
0.2
0.25
0.3
Frequency (normalized to Fs)
Figure 35. ADC Passband Ripple
High−Pass Filter Response (Fs = 48kHz)
0
−3
0.6
0.58
0
−6
0.46
0.56
Passband Ripple
Transition Band (Detail)
0
−10
0.45
0.54
Figure 33. ADC Transition Band
18
20
−3
0
2
4
6
8
10
Frequency (Hz)
12
14
16
18
20
Figure 37. ADC HPF (96 kHz)
70
CS4234
8. DAC FILTER PLOTS
DS899F1
Figure 38. SSM DAC Stopband Rejection
Figure 39. SSM DAC Transition Band
Figure 40. SSM DAC Transition Band (Detail)
Figure 41. SSM DAC Passband Ripple
71
CS4234
DS899F1
Figure 42. DSM DAC Stopband Rejection
Figure 43. DSM DAC Transition Band
Figure 44. DSM DAC Transition Band (Detail)
Figure 45. DSM DAC Passband Ripple
72
CS4234
9. PACKAGE DIMENSIONS
40L QFN (6  6 MM BODY) PACKAGE DRAWING
D
b
2.00REF
e
PIN #1CORNER
2.00REF
PIN #1IDENTIFIER
0.500.10
LASER MARKING
E2
E
A1
L
D2
A
Figure 46. Package Drawing
INCHES
MILLIMETERS
NOTE
DIM
MIN
NOM
MAX
MIN
NOM
MAX
A
—
—
0.0394
—
—
1.00
1
A1
0.0000
—
0.0020
0.00
—
0.05
1
b
0.0071
0.0091
0.0110
0.18
0.23
0.28
1,2
D
D2
0.2362 BSC
0.1594
E
E2
0.1634
4.05
0.2362 BSC
0.1594
e
L
.1614
6.00 BSC
.1614
0.0157
4.15
6.00 BSC
0.1634
4.04
0.0197 BSC
0.0118
4.10
1
4.10
1
4.15
0.50 BSC
0.0197
0.30
0.40
1
1
1
0.50
1
JEDEC #: MO-220
Controlling Dimension is Millimeters.
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.
DS899F1
73
CS4234
10.ORDERING INFORMATION
Product
CS4234
Description
4 In/5 Out CODEC
with Programmable
Group Delay
Package Pb-Free
40-QFN
Yes
Grade
Temp Range Container
Automotive -40° to +105°C
Order#
Rail
CS4234-ENZ
Tape and
Reel
CS4234-ENZR
11.APPENDIX A: INTERNAL TRACKING POWER SUPPLY SIGNAL
The tracking signal for a Class H amplifier tracks the envelope of the maximum of any arbitrary number of input signals (up to 32 channels for the CS4234). This tracking signal is used to modulate the output voltage of a switch mode
power supply (SMPS), which serves as the rail voltages for an audio amplifier. The main goal in any tracking algorithm is to maximize the efficiency of the Class H amplifier by creating a signal that causes the rails of the SMPS,
sometimes referred to as a tracking power supply or TPS, to track the amplified audio signal as closely as possible.
However, the tracking algorithm must also ensure that the amplifier never clips due to the rail voltage being brought
too low relative to the output voltage swing of the audio amplifier.
In order to track the output voltage swing of the amplifier without causing clipping, three controls are provided to
ensure the tracking signal stays above (higher amplitude) and ahead of (occurs earlier in time) the output voltage
swing of the amplifier. These controls and their respective effects on the tracking signal output on DAC5 are detailed
in Figure 47 and listed in the following sections.
With the exception of the Gain Matching control, the appropriate levels for the tracking controls are usually determined experimentally, on an application by application basis. The reason is because the transitioning speed, or
bandwidth, of the SMPS is heavily influenced by the capacitance connected to the output nets of the SMPS, the
topology of the SMPS, the modulation technique, and the bandwidth of the error amplifier in the feedback loop.
DS899F1
74
DS899F1
0V
0V
Ch. 3
Ch. 4
Ch. n
0V
Ch. 2
.
.
.
.
0V
Ch. 1
Signals Coming into the Tracking Engine
for simplicity only
Ch. 1 is tracked
Signal Going out of the Block
Signal Coming into the Block
Signal Color Key:
AIN1 (±)
AIN2 (±)
AIN3 (±)
AIN4 (±)
Mute, Invert,
Noise Gat e
Ch. Volume,
Mute, I nvert,
Noise Gate
DAC
Volume
TPS
GAI N
Gain / Volume
0V
X
X
Frame Sync
Clock / LRCK
Sample
& Hold
Master
Volume
Cont rol
Select
Mode
Select

2.5 V


INT

Multi-bit 
Modulators
RST
I2 C Cont rol
Data
DAC &
Analog
Filters
Analog Supply
DAC &
Analog
Filters
VA
5.0 VDC
0V
Multi-bit 
Modulat ors
Cont rol Port
Sample & Hold

LDO
Full Scale Code
I nterpolation Filter
Serial Clock
In / Out
Interpolation
Filt er
Filter
Select
Master Clock In
K4
0 dB
X
Gain
Select
-1 -2
VD
2. 5 VDC
Envelope of Abs. Max with
Gain Applied via DAC5
Volume Control Register
Mast er Volume
DC Offset
Master
Vol. Cntrl
Level Translator
Serial Audio Int erface
K3
SDIN1
0-500uS
Group
Delay
K1
Envelope
Tracking
Mute, Invert,
Noise Gat e
Max
Detect
SDOUTx
SDIN2
5t h DAC
I nput Advisory
Tracking
SMPS
Enable
Low-Latency
Demux
0V
Digital Filters
Multi-bit
 ADC
VL
1.8 t o 5.0 VDC
Abs. Max
Envelope of Abs.
Max
0V
K2
K5
Supply Rails
Switch mode Power Supply
Configured to be Referenced
to Full Scale by setting TPS
Mode Register to “1”
Envelope of Abs. Max with
Gain and DC Offset Applied
via TPS OFFSET Register
0V
-2 gain
-1 gain
Full Scale
CS4234
Voltage
&
Current Gain
Figure 47. Progression of the Tracking Signal Through the DAC5 Path
75
CS4234
11.1
Voltage Headroom
Headroom is another word for the static DC offset inserted into the tracking signal. This offset allows the rail
voltages to track the audio amplifier outputs with a sufficient amount of voltage such that a sudden audio
bandwidth transition (i.e. 20 kHz or less) across the full dynamic range of the audio amplifier (i.e from 0 V
input to full scale input) will not cause the amplifier to clip. This control is contained within the DC Offset
block highlighted in yellow in Figure 47.
Adjustment to the DC offset is done through the TPS OFFSET[2:0] bits in the "TPS Control" register. The
offset is given in terms of %Full Scale, since the output voltage of the DACs are given relative to VA.
The DC offset applied to the tracking signal affects both the efficiency of the Class H amplifier and the ability
of the SMPS to respond to high amplitude transients. By having a smaller DC Offset, the power that is wasted in the output stage of the audio amplifier is reduced. However, since the speed at which the SMPS rail
voltages change depends heavily on the bulk capacitance attached to its outputs, providing too small of a
DC offset may not provide enough head room for the SMPS to maintain an unclipped audio signal during
the time that the rail voltage transitions are charging the bulk capacitance.
Also, unless the resting voltage of the SMPS is set by some other means within the SMPS, the lowest possible DC offset value is dictated by the minimum operating threshold of the audio amplifier attached to the
rails of the SMPS. The DC offset, multiplied by the gain of the SMPS “K2”, cannot be less than the amplifier’s
operating threshold. If this occurs, the undervoltage lockout protection of the audio amplifier (if equipped)
engages prematurely when the rails collapse to a level lower than the allowable operating threshold.
11.2
Lead Time
Lead time is a static time interval that allows the SMPS rails to begin to transition before the amplified audio
output signal begins to transition. This is accomplished by delaying the outgoing audio signal sufficiently to
prevent the amplified output signal from transitioning faster than the rails can transition. This control is provided by the programmable Group Delay block highlighted in red in Figure 47.
As was the case with the DC offset, there is a connection between the group delay applied to the audio signal, the efficiency of the Class H amplifier, and the ability of the SMPS to respond to high amplitude transients. By having a shorter delay, the output voltage of the SMPS can track the audio signal more closely,
increasing efficiency of the Class H system by reducing wasted power in the amplifier output devices. However, providing too short of a delay may not provide enough lead time for the SMPS to react to high frequency, high-amplitude transients, which will result in clipping of the output signal. For these reasons, the group
delay of the CS4234 can be adjusted from 100 s to 500 s, based on the GROUP DELAY[3:0] setting.
11.3
Gain Matching
Gain matching is necessary to ensure that the gain of the path of the SMPS path is the same as the audio
path. The SMPS path consists of the DAC5 path, the SMPS modulator, and the voltage conversion ratio of
the SMPS and any components between DAC5 and the SMPS modulator. The audio path consists of
DAC1-4 path and the audio amplifier and any components between them. The gains present in each of the
blocks of interest are shown in Figure 47 as K1 through K5. The gain matching block “K1”, highlighted in
violet, provides the means to ensure that the total gain of the SMPS path, which consists of K1*K4(if applicable)*K2, is as close as possible to the audio path gain, comprised of K3*K4*K5. If the “K3” channel gain
is not equal for all channels, use the maximum channel’s gain during this matching calculation to prevent
clipping on any channel.
As much as +6 dB of gain and as much as -83 dB of attenuation can be applied to the tracking signal in
approximately 0.4 dB steps, although a much smaller range centered around 0 dB is likely. To match the
gains between the SMPS and the amplifier, calculate the gain of the audio path and add gain or attenuation
as necessary to the SMPS path to make the gains of both paths equal. The addition of gain or attenuation
is accomplished via the DAC5 VOLUME[7:0] bits.
DS899F1
76
CS4234
11.3.1
SMPS Voltage Conversion Gain (K2)
The gain of the SMPS voltage conversion, in units of V/V, can be determined by dividing the maximum
voltage of the SMPS by the maximum voltage permitted by the SMPS modulator stage. Preferably, the
maximum voltage permitted by the modulator will be equal to the full scale voltage of DAC5. If it is not,
the gain (or attenuation) of any circuitry between the outputs of DAC5 and the modulator must be taken
into account. For a differential SMPS, the maximum voltage is represented by VP+ - VP-. For single-ended supplies, the maximum voltage is simply the largest single ended voltage that the SMPS can create.
11.3.2
Amplifier Gain Path (K5)
The amplifier gain is simply the gain applied to the output audio signal by the power amplifier. It is important to note, however, that if different gain amplifiers are all connected to the SMPS, the highest gain setting should be used to set the gain of the SMPS path.
11.4
SMPS (TPS) Modes
The voltage output of a SMPS should be linear and will operate in one of two modes, depending on the topology and modulation of the SMPS. In Mode 0, the SMPS output voltage will be directly proportional to the
control signal amplitude. In Mode 1, the SMPS output voltage will be inversely proportional to the control
signal amplitude. The transfer function for each mode, which details this behavior, is shown in Figure 48.
Max
SMPS
Rail
Voltage
Directly Proportional (Mode 0):
Inversely Proportional (Mode 1):
Min
Min
SMPS
Control
Signal
Max
Figure 48. Directly Proportional vs. Indirectly Proportional Modes of Operation
Because of these different modes of operation for the SMPS, it is necessary that the control signal be referenced to 0 V when the SMPS is operated in Mode 0 and referenced to the full scale output voltage of the
DAC when the SMPS is operated in Mode 1. To allow the control signal from DAC5 of the CS4234 to be
configured for both modes of operation, the TPS MODE bit in the "TPS Control" register is provided. The
TPS GAIN bit in the "DAC Control 4" register can be used to modify the control signal in mode 1. Figure 49
shows both the single-ended and differential output signals for each mode of operation. Figure 50 shows
how modifying the TPS OFFSET[2:0] and DAC5 VOLUME[7:0] controls affect the transfer functions in each
mode.
DS899F1
77
CS4234
AOUT5+
VA/2
AOUT5+
VA/2
0V
0V
Digital "0"
0V
Digital "0"
Full Scale
Digital Audio Input
to DAC5 Path
AOUT5-
Digital "0"
Full Scale
Digital Audio Input
to DAC5 Path
AOUT5-
Digital "0"
0V
Full Scale
Digital Audio Input
to DAC5 Path
Full Scale
Digital Audio Input
to DAC5 Path
Full Scale
VA/2
0.5xFull Scale
0V
Digital Audio Input
to DAC5 Path
AOUT5-
VA/2
0.5xFull Scale
VA/2
Full Scale
VA/2
Full Scale
AOUT5+
Mode 1 TPS Gain = 1
0.5xFull Scale
Mode 1 TPS Gain = 0
0.5xFull Scale
Mode 0
Digital "0"
0V
Full Scale
Digital Audio Input
to DAC5 Path
Digital "0"
SMPS Control
(AOUT5+ - AOUT5-)
0.5xFull Scale
0.5xFull Scale
VA/2
SMPS Control
(AOUT5+ - AOUT5-)
VA/2
0V
Digital "0"
0V
Digital Audio Input
to DAC5 Path
Full Scale
Full Scale
VA/2
SMPS Control
(AOUT5+ - AOUT5-)
0V
Digital Audio Input
to DAC5 Path
Digital "0"
Full Scale
Digital Audio Input
to DAC5 Path
Digital "0"
Full Scale
-VA/2
Figure 49. DAC5 TPS Modes of Operation
lu me
5 vo
VA/2
inc re
AOUT5+
d ecre
ase
ase T
DA C
PS o
5 vo
ffs et
lu me
VA/2
0V
VA/2
inc
re
Full Scale
Digital Audio Input
to DAC5 Path
Digital "0"
Digital "0"
Full Scale
Digital Audio Input
to DAC5 Path
olum
e
Full Scale
Digital Audio Input
to DAC5 Path
t
off se
lu me
TP S
5 vo
as e
DA C
inc re
ease
decr
0V
Digital "0"
SMPS Control
(AOUT5+ - AOUT5-)
T
se
rea
inc
VA/2
as
decre
PS
t
e
olum
C5 v
e DA
a se
DA C
5 vol
um
So
ffs
et
e
AC 5
v
olum
e
inc
rea
se
0V
Digital "0"
Digital Audio Input
to DAC5 Path
TP
So
ffs
et
Full Scale
Digital Audio Input
to DAC5 Path
e
de cr
PS
se
off
AC
ase D
t
lum
5 vo
e
0V
Digital "0"
Full Scale
Digital Audio Input
to DAC5 Path
decr
eas e
D
VA/2
0.5xFull Scale
SMPS Control
(AOUT5+ - AOUT5-)
se
off
0.5xFull Scale
dec re
se T
as e
PS o
D AC
ff set
5v
VA/2
VA/2
0.5xFull Scale
inc re
a
0V
0.5xFull Scale
VA/2
TP
T
se
rea
inc
AOUT5-
AOUT5-
AOUT5-
de cre
as
e
0V
0V
Digital "0"
Digital "0"
AOUT5+
Full Scale
DA C
Full Scale
ase
d ecr e
Full Scale
Digital Audio Input
to DAC5 Path
SMPS Control
(AOUT5+ - AOUT5-)
VA/2
de
cre
as
eD
AC
5v
0V
Digital "0"
Full Scale
ol u
m
Digital Audio Input e
to DAC5 Path
Full Scale
Full Scale
t
off se
0.5xFull Scale
PS
ase T
incre
AOUT5+
Mode 1 TPS Gain = 1
Mode 1 TPS Gain = 0
0.5xFull Scale
Mode 0
0V
Digital Audio Input
to DAC5 Path
Full Scale
- VA/2
-VA/2
se
ea
cr
in
Digital "0"
S
TP
et
fs
of
Figure 50. DAC5 Volume and TPS Offset Controls
DS899F1
78
CS4234
12.REVISION HISTORY
Release
Changes
F1
– Added left justified and I2S serial ports to system features on front page.
– Renamed the FS pin to FS/LRCK throughout.
– Renamed the SDOUT pin to SDOUT1 throughout and updated the SDOUT1 pin description in Section 1 to
include in left justified and I²S modes.
– Renamed the AD2 pin to AD2/SDOUT2 throughout and updated the pin description in Section 1 to reflect
the combined functionality of the input/output pin, and updated figures throughout to show as bidirectional
signal.
– Changed SCLK from “Input” to “Input/Output” in pin description in Section 1.
– Updated Section 1.1 to reflect the pin name changes.
– Updated “Switching Characteristics - Serial Audio Interface” on page 18 to include slave and master modes.
– Added Figure 6. TDM Serial Audio Interface Timing and Figure 7. PCM Serial Audio Interface Timing.
– Updated Section 4.4 for master/slave mode and left justified/I²S mode functionality.
– Added Section 4.5.2 Left Justified and I²S Modes.
– Added left justified and I²S mode data routing description to Section 4.6.1.1 ADC Signal Routing and Section
4.6.1.2 DAC1-4, DAC5, and Low-latency Signal Routing.
– Added I2S and left-justified options SP_FORMAT field (reg 08h bits 3:2) in Section 6.5.3 Serial Port Format
– Added MASTER/SLAVE bit (reg 08h bit 0) to Section 5. Register Quick Reference and Section 6.5 Serial
Port Control (Address 08h) and added description, Section 6.5.5 Master / Slave.
– Updated PSRR specification in the Analog Input Characteristics table.
– Removed note about ADC CM bits in the Analog Input Characteristics table.
– Added analog input pins must be externally biased in Section 4.6.2.1.
– Changed ADC CM bits to reserved in Section 5 and Section 6.6.
– Changed references to PA117 to CS44417 throughout.
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
Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable. However, the information is subject
to change without notice and is provided “AS IS” without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale
supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus
for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third
parties. This document is the property of Cirrus and by furnishing this information, Cirrus grants no license, express or implied under any patents, mask work rights,
copyrights, trademarks, trade secrets or other intellectual property rights. Cirrus owns the copyrights associated with the information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Cirrus integrated circuits or other products of Cirrus. This consent
does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED FOR USE
IN PRODUCTS SURGICALLY IMPLANTED INTO THE BODY, AUTOMOTIVE SAFETY OR SECURITY DEVICES, LIFE SUPPORT PRODUCTS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF CIRRUS PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK AND CIRRUS DISCLAIMS AND MAKES NO WARRANTY, EXPRESS, STATUTORY OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR PARTICULAR PURPOSE, WITH REGARD TO ANY CIRRUS PRODUCT THAT IS USED IN SUCH A MANNER. IF THE CUSTOMER OR CUSTOMER’S CUSTOMER USES OR PERMITS THE USE OF CIRRUS PRODUCTS IN CRITICAL APPLICATIONS, CUSTOMER AGREES, BY SUCH USE, TO FULLY
INDEMNIFY CIRRUS, ITS OFFICERS, DIRECTORS, EMPLOYEES, DISTRIBUTORS AND OTHER AGENTS FROM ANY AND ALL LIABILITY, INCLUDING ATTORNEYS’ FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES.
Cirrus Logic, Cirrus and the Cirrus Logic logo designs 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 trademark of Philips Semiconductor.
DS899F1
79