w WM8741
24-bit 192kHz DAC with Advanced Digital Filtering
WOLFSON MICROELECTRONICS plc
Production Data, February 2013, Rev 4.3
Copyright 2013 Wolfson Microelectronics plc
DESCRIPTION
The WM8741 is a very high performance stereo DAC
designed for audio applications such as professional
recording systems, A/V receivers and high specification CD,
DVD and home theatre systems. The device supports PCM
data input word lengths from 16 to 32-bits and sampling
rates up to 192kHz. The WM8741 also supports DSD bit-
stream data format, in both direct DSD and PCM-converted
DSD modes.
The WM8741 includes fine resolution volume and soft mute
control, digital de-emphasis and a range of advanced digital
filter responses, followed by a digital interpolation filter,
multi-bit sigma delta modulator and stereo DAC. Wolfson’s
patented architecture optimises the linearity of the DAC and
provides maximum insensitivity to clock jitter.
The digital filters include several selectable roll-off and
performance characteristics. The user can select between
standard sharp or slow roll-off responses. In addition, the
WM8741 includes a selection of advanced digital filter
characteristics including non-half band filters and minimum
phase filters.
This flexibility provides a range of benefits, such as
significantly reduced pre-ringing and minimal group delay.
The internal digital filters can also be by-passed and the
WM8741 used with an external digital filter.
The WM8741 supports two connection schemes for audio
DAC control. The 2/3 wire serial control interface provides
access to all features. A range of features can also be
accessed by hardware control interface.
The WM8741 is available in a convenient 28-SSOP
package, and is pin compatible with the WM8740.
FEATURES
Advanced Ultra High Performance Multi-bit Sigma-Delta
Architecture
128dB SNR (‘A’-weighted mono @ 48kHz)
125dB SNR (‘A’-weighted stereo @ 48kHz)
123dB SNR (non-weighted stereo @ 48kHz)
-100dB THD @ 48kHz
Differential analogue voltage outputs
High tolerance to clock jitter
PCM Mode
Sampling frequency: 32kHz to 192kHz
Input data word length support: 16 to 32-bit
Supports all standard audio interface formats
Selectable advanced digital filter responses
Includes linear/minimum phase and range of
tailored characteristics
Enables low pre-ringing, minimal latency
Optional interface to industry standard external filters
Digital volume control in 0.125dB steps with soft ramp
and soft mute
Anti-clipping mode to prevent distortion even with input
signals recorded up to 0dB
Selectable de-emphasis support
Zero Flag output
DSD Mode
DSD bit-stream support for SACD applications
Support for normal or phase modulated bit-streams
Direct or PCM converted DSD paths (DSD Plus)
DSD mute
Hardware or software control modes:
2 and 3 wire serial control interface support
Pin compatible with WM8740
4.5V to 5.5V analogue, 3.15V to 3.6V digital supply
operation
28-lead SSOP Package
APPLICATIONS
Professional audio systems
CD, DVD, SACD audio
Home theatre systems
A/V receivers
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BLOCK DIAGRAM
DSD
ATTENUATION /
MUTE
DSD TO PCM
CONVERTOR
PCM
ATTENUATION /
MUTE
AUDIO
INTERFACE
PCM DIGITAL FILTERS
SIGMA DELTA
MODULATOR
CONTROL INTERFACE
PCM
DSD
PCM
ATTENUATION /
MUTE
SIGMA DELTA
MODULATOR
MUTEB/SDOUT
MODE/LRSEL
CSB/SADDR/I2S
SDIN/DEEMPH
SCLK/DSD
ZFLAG
DIFFHW
DAC
LEFT
DAC
RIGHT
VMIDL
VOUTLP
VOUTLN
VOUTRP
VOUTRN
VMIDR
AGNDL
AVDDL
AGNDR
AVDDR
AGND
AVDD
MCLK
OSR/DSDR
IWO/DOUT
LRCLK/DSDL
DIN/DINL
FSEL/DINR
BCLK/DSD64CLK
PCM/DSD MUX
WM8741
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TABLE OF CONTENTS
DESCRIPTION ....................................................................................................... 1
FEATURES ............................................................................................................ 1
APPLICATIONS ..................................................................................................... 1
BLOCK DIAGRAM ................................................................................................ 2
TABLE OF CONTENTS ......................................................................................... 3
PIN CONFIGURATION .......................................................................................... 4
ORDERING INFORMATION .................................................................................. 4
PIN DESCRIPTION (SOFTWARE CONTROL MODE) .......................................... 5
PIN DESCRIPTION (HARDWARE CONTROL MODE) ......................................... 7
ABSOLUTE MAXIMUM RATINGS ........................................................................ 9
THERMAL PERFORMANCE ................................................................................. 9
RECOMMENDED OPERATING CONDITIONS ................................................... 10
ELECTRICAL CHARACTERISTICS ................................................................... 10
MASTER CLOCK TIMING ............................................................................................. 12
PCM DIGITAL AUDIO INTERFACE TIMINGS .............................................................. 12
DSD AUDIO INTERFACE TIMINGS.............................................................................. 13
CONTROL INTERFACE TIMING – 3-WIRE MODE ...................................................... 14
CONTROL INTERFACE TIMING – 2-WIRE MODE ...................................................... 15
INTERNAL POWER ON RESET CIRCUIT .................................................................... 16
DEVICE DESCRIPTION ...................................................................................... 18
INTRODUCTION ........................................................................................................... 18
CLOCKING SCHEMES ................................................................................................. 18
CONTROL INTERFACE ................................................................................................ 18
SOFTWARE CONTROL INTERFACE........................................................................... 19
DIGITAL AUDIO INTERFACE ....................................................................................... 21
DSD MODE ................................................................................................................... 27
SOFTWARE CONTROL MODE .................................................................................... 28
HARDWARE CONTROL MODE.................................................................................... 39
OVERVIEW OF FUNCTIONS .............................................................................. 43
REGISTER MAP .................................................................................................. 44
DIGITAL FILTER CHARACTERISTICS .............................................................. 50
PCM MODE FILTER CHARACTERISTICS ................................................................... 50
8FS MODE FILTER CHARACTERISTICS .................................................................... 52
DSD PLUS MODE FILTER CHARACTERISTICS ......................................................... 53
PCM MODE FILTER RESPONSES .............................................................................. 54
8FS MODE FILTER RESPONSES ................................................................................ 59
DSD PLUS MODE FILTER RESPONSES .................................................................... 59
DSD DIRECT MODE FILTER RESPONSES ................................................................ 60
DEEMPHASIS FILTER RESPONSES........................................................................... 62
APPLICATIONS INFORMATION ........................................................................ 63
PACKAGE DIMENSIONS .................................................................................... 64
IMPORTANT NOTICE ......................................................................................... 65
ADDRESS: .................................................................................................................... 65
REVISION HISTORY ........................................................................................... 66
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PIN CONFIGURATION
ORDERING INFORMATION
DEVICE TEMPERATURE
RANGE PACKAGE MOISTURE SENSITIVITY
LEVEL
PEAK SOLDERING
TEMPERATURE
WM8741GEDS/V -0 to +70C 28-lead SSOP
(Pb-free) MSL2 260˚C
WM8741GEDS/RV -0 to +70C 28-lead SSOP
(Pb-free, tape and reel) MSL2 260˚C
Note:
Reel Quantity = 2,000
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PIN DESCRIPTION (SOFTWARE CONTROL MODE)
PIN NAME TYPE DESCRIPTION
PCM MODE 8FS PCM MODE DSD MODES
1 LRCLK /
DSDL
Digital input Audio interface left/right
clock input
Audio interface left/right
clock input
DSD left audio data in
2 DIN /
DINL
Digital input Audio interface data input Audio interface left data
input
Unused
3 BCLK /
DSD64CLK
Digital input Audio interface bit clock
input
Audio interface bit clock
input
64fs system clock input
4 FSEL /
DINR
Digital input
Tri-level
Unused Audio interface right data
input
Unused
5 MCLK Digital input
Master clock input Master clock input Unused
6 DIFFHW Digital input
Internal pull-
down
Differential mono mode
selection
0 = normal operation
1 = differential mono
mode
Differential mono mode
selection
0 = normal operation
1 = differential mono
mode
Differential mono mode
selection
0 = normal operation
1 = differential mono
mode
7 DGND Supply
Digital ground Digital ground Digital ground
8 DVDD Supply
Digital supply Digital supply Digital supply
9 AVDDR Analogue Input
Right analogue positive
reference
Right analogue positive
reference
Right analogue positive
reference
10 AGNDR Analogue Input
Right analogue negative
reference
Right analogue negative
reference
Right analogue negative
reference
11 VMIDR Analogue
Output
Right analogue midrail
decoupling pin
Right analogue midrail
decoupling pin
Right analogue midrail
decoupling pin
12 VOUTRP Analogue
Output
Right DAC positive
output
Right DAC positive
output
Right DAC positive
output
13 VOUTRN Analogue
Output
Right DAC negative
output
Right DAC negative
output
Right DAC negative
output
14 AGND Supply
Analogue ground Analogue ground Analogue ground
15 AVDD Supply
Analogue supply Analogue supply Analogue supply
16 VOUTLN Analogue
Output
Left DAC negative output Left DAC negative output Left DAC negative output
17 VOUTLP Analogue
Output
Left DAC positive output Left DAC positive output Left DAC positive output
18 VMIDL Analogue
Output
Left analogue midrail
decoupling pin
Left analogue midrail
decoupling pin
Left analogue midrail
decoupling pin
19 AGNDL Analogue Input
Left analogue negative
reference
Left analogue negative
reference
Left analogue negative
reference
20 AVDDL Analogue Input
Left analogue positive
reference
Left analogue positive
reference
Left analogue positive
reference
21 ZFLAG Digital Output
Zero flag output Zero flag output Zero flag output
22 OSR/DSDR Digital input
Tri-level
Unused Unused DSD right audio data in
23 IWO /
DOUT
Digital
input/output
Buffered audio interface
data output
Unused Unused
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PIN NAME TYPE DESCRIPTION
PCM MODE 8FS PCM MODE DSD MODES
24 MODE /
LRSEL
Digital input,
tri-level
When DIFFHW=0:
0 = hardware mode
1 = 3-wire software mode
Z = 2-wire software mode
When DIFFHW=1:
0 = left channel mono
1 = right channel mono
When DIFFHW=0:
0 = hardware mode
1 = 3-wire software mode
Z = 2-wire software mode
When DIFFHW=1:
0 = left channel mono
1 = right channel mono
When DIFFHW=0:
0 = hardware mode
1 = 3-wire software mode
Z = 2-wire software mode
When DIFFHW=1:
0 = left channel mono
1 = right channel mono
25 MUTEB /
SDOUT
Digital input or
output:
Internal pull-up
Softmute Control
0 = mute active
1 = normal operation
NOTE: In 3-wire mode
only, this pin may be
used as a buffered
control interface data
output
Softmute Control
0 = mute active
1 = normal operation
Softute Control
0 = mute active
1 = normal operation
Note: In DSD Direct
mode this is an analogue
mute
26 SDIN /
DEEMPH
Digital input
Tri-level
Serial control interface
data input
Serial control interface
data input
Serial control interface
data input
27 SCLK /
DSD
Digital input Serial control interface
clock input
Serial control interface
clock input
Serial control interface
clock input
28 CSB /
SADDR /
I2S
Digital input
3-wire mode: serial
control interface latch
2-wire mode: device
address select
3-wire mode: serial
control interface latch
2-wire mode: device
address select
3-wire mode: serial
control interface latch
2-wire mode: device
address select
Notes:
1. Undefined inputs should be connected to DVDD or DGND
2. Tri-level pins which require the ‘Z’ state to be selected should be left floating (open)
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PIN DESCRIPTION (HARDWARE CONTROL MODE)
PIN NAME TYPE DESCRIPTION
PCM MODE DSD DIRECT MODE
1 LRCLK /
DSDL
Digital input Audio interface left/right clock input DSD left audio data in
2 DIN /
DINL
Digital input Audio interface data input Unused
3 BCLK /
DSD64CLK
Digital input Audio interface bit clock input 64fs system clock input
4 FSEL /
DINR
Digital input
Tri-level
Selects between one of three digital
filters – see Table 50
Unused
5 MCLK Digital input
Master clock input Unused
6 DIFFHW Digital input
Internal pull-
down
Differential mono mode selection
0 = normal operation
1 = differential mono mode
Differential mono mode selection
0 = normal operation
1 = differential mono mode
7 DGND Supply
Digital ground Digital ground
8 DVDD Supply
Digital supply Digital supply
9 AVDDR Analogue Input
Right analogue positive reference Right analogue positive reference
10 AGNDR Analogue Input
Right analogue negative reference Right analogue negative reference
11 VMIDR Analogue
Output
Right analogue midrail decoupling pin Right analogue midrail decoupling pin
12 VOUTRP Analogue
Output
Right DAC positive output Right DAC positive output
13 VOUTRN Analogue
Output
Right DAC negative output Right DAC negative output
14 AGND Supply
Analogue ground Analogue ground
15 AVDD Supply
Analogue supply Analogue supply
16 VOUTLN Analogue
Output
Left DAC negative output Left DAC negative output
17 VOUTLP Analogue
Output
Left DAC positive output Left DAC positive output
18 VMIDL Analogue
Output
Left analogue midrail decoupling pin Left analogue midrail decoupling pin
19 AGNDL Analogue Input
Left analogue negative reference Left analogue negative reference
20 AVDDL Analogue Input
Left analogue positive reference Left analogue positive reference
21 ZFLAG Digital Output
Zero flag output Unused
22 OSR/DSDR Digital input
Tri-level
Controls internal oversampling rate:
0 = low rate
Z = medium rate
1 = high rate
DSD right audio data in
23 IWO /
DOUT
Digital
input/output
Controls audio interface wordlength –
see Table 46
Unused
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PIN NAME TYPE DESCRIPTION
PCM MODE DSD DIRECT MODE
24 MODE /
LRSEL
Digital input,
tri-level
When DIFFHW=0:
0 = hardware mode
1 = 3-wire software mode
Z = 2-wire software mode
When DIFFHW=1:
0 = left channel mono
1 = right channel mono
When DIFFHW=0:
0 = hardware mode
1 = 3-wire software mode
Z = 2-wire software mode
When DIFFHW=1:
0 = left channel mono
1 = right channel mono
25 MUTEB /
SDOUT
Digital input or
output:
Internal pull-up
Softmute Control
0 = mute active
1 = normal operation
Analogue Mute Control
0 = mute active
1 = normal operation
26 SDIN /
DEEMPH
Digital input
Tri-level
De-emphasis Control
0 = normal operation
1 = de-emphasis applied
Z = anti-clipping digital filter mode
Unused
27 SCLK /
DSD
Digital input HW Mode Select:
0 = PCM
1 = DSD Direct
HW Mode Select:
0 = PCM
1 = DSD Direct
28 CSB /
SADDR /
I2S
Digital input
Controls audio interface format – see
Table 46
Unused
Notes:
1. Undefined inputs should be connected to DVDD or DGND
2. Tri-level pins who require the ‘Z’ state to be selected should be left floating (open)
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ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at
or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical
Characteristics at the test conditions specified.
ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible
to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage
of this device.
Wolfson Microelectronics tests its package types according to IPC/JEDEC J-STD-020 for Moisture Sensitivity to determine
acceptable storage conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in Ordering Information.
CONDITION MIN MAX
Digital supply voltage, DVDD -0.3V +4.5V
Analogue supply voltage, AVDD -0.3V +7V
Voltage range digital inputs DGND - 0.3V DVDD + 0.3V
Voltage range analogue inputs AGND - 0.3V AVDD + 0.3V
Master Clock Frequency 38.462MHz
Operating temperature range, TA -0°C +70°C
Storage temperature -65°C +150°C
Ambient temperature (supplies applied) -55°C +125°C
Pb free package body temperature (soldering 10 seconds) +260°C
Pb free package body temperature (soldering 2 minutes) +183°C
Notes:
1. Analogue and digital grounds must always be within 0.3V of each other.
THERMAL PERFORMANCE
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Thermal resistance –
junction to case
θJC 23.9 °C/W
Thermal resistance –
junction to ambient
θJA 67.1 °C/W
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RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Digital supply range DVDD 3.15 3.3 3.6 V
Analogue supply range AVDD 4.5 5 5.5 V
Ground AGND, DGND 0 V
Difference DGND to AGND -0.3 0 +0.3 V
Analogue operating current IAVDD AVDD = 5V 55 mA
Digital operating current IDVDD DVDD = 3.3V 40 mA
Analogue standby current IAVDD (Standby) AVDD = 5V
Clocks stopped
45 mA
Digital standby current IDVDD (Standby) DVDD = 3.3V
Clocks stopped
1.5 mA
ELECTRICAL CHARACTERISTICS
TEST CONDITIONS
AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, TA = +25oC, 1kHz test signal, fs = 48kHz, MCLK = 512fs unless otherwise
stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Digital Logic Levels
Input LOW level VIL 0.3 x DVDD V
Input HIGH level VIH 0.7 x DVDD V
Output LOW level VOL I
OL = 2mA 0.1 x DVDD V
Output HIGH level VOH I
OH = 2mA 0.9 x DVDD V
DSD Input Characteristics
DSD reference level DSD Direct or DSD Plus Mode 0
50
dBDSD
%
DAC Performance
Signal to Noise Ratio
(Note 1)
SNR A-weighted mono
@ fs = 48kHz
128 dB
A-weighted stereo
@ fs = 48kHz
120 125 dB
A-weighted stereo
@ fs = 96kHz
123 dB
A-weighted stereo
@ fs = 192kHz
120 dB
Non-weighted stereo
@ fs = 48kHz
122 dB
Dynamic Range
(Note 2)
DNR A=weighted,
-60dB full scale input
125 dB
Total Harmonic Distortion
(Note 2)
THD Mono 0dB @ fs = 48kHz -100 dB
Stereo 0dB @ fs = 48kHz -100 dB
Stereo 0dB @ fs = 96kHz -100 dB
Stereo 0dB @ fs = 192kHz -100 dB
Channel Separation 1kHz 130 dB
Channel Level Matching 0.1 dB
Channel Phase Deviation 0.01 Degree
Power Supply Rejection
Ratio
PSRR 100mVpp at 1kHz -80 dB
20Hz to 20kHz 100mVpp -67 dB
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TEST CONDITIONS
AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, TA = +25oC, 1kHz test signal, fs = 48kHz, MCLK = 512fs unless otherwise
stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Internal Analogue Filter
Bandwidth -3dB 474 kHz
Passband edge response 20kHz -0.0077 dB
Analogue Output Levels
PCM full scale differential
output level
Into 10k load, 0dBFS input 2 VRMS
DSD Direct differential
output level
Into 10k load, 0dBDSD input 0.948 VRMS
DSD Plus differential output
level
Into 10k load, 0dBDSD input 0.991 VRMS
Minimum resistance load To midrail or AC coupled 2 k
Maximum capacitance load 1 nF
Output DC level AVDD/2 V
Reference Levels
Potential divider resistance AVDD to VMIDL/VMIDR and
VMIDL/VMIDR to AGND
10 k
Voltage at VMIDL/VMIDR AVDD/2 V
Notes:
1. Ratio of output level with 1kHz full scale input, to the output level with all zeros into the digital input, measured ‘A’
weighted over a 20Hz to 20kHz bandwidth.
2. All performance measurements done with 20kHz low pass filter. Failure to use such a filter will result in higher THD
and lower SNR and Dynamic Range readings than are found in the Electrical Characteristics. The low pass filter
removes out of band noise; although it is not audible it may affect dynamic specification values.
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MASTER CLOCK TIMING
Figure 1 Master Clock Timing Requirements
Test Conditions
AVDD = 5V, DVDD = 3.3V, AGND = 0V, DGND = 0V, TA = +25oC
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Master Clock Timing Information
MCLK Master clock pulse width high tMCLKH 10 ns
MCLK Master clock pulse width low tMCLKL 10 ns
MCLK Master clock cycle time tMCLKY 27 ns
MCLK Duty cycle 40:60 60:40
Table 1 MCLK Timing Requirements
PCM DIGITAL AUDIO INTERFACE TIMINGS
Figure 2 Digital Audio Data Timing
Test Conditions
AVDD = 5V, DVDD = 3.3V, AGND = 0V, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Audio Data Input Timing Information
BCLK cycle time tBCY 40 ns
BCLK pulse width high tBCH 16 ns
BCLK pulse width low tBCL 16 ns
LRCLK set-up time to BCLK
rising edge
tLRSU 8 ns
LRCLK hold time from
BCLK rising edge
tLRH 8 ns
DIN set-up time to BCLK
rising edge
tDS 8 ns
DIN hold time from BCLK
rising edge
tDH 8 ns
Table 2 Digital Audio Interface Timing Requirements
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DSD AUDIO INTERFACE TIMINGS
DSDCLK64
DSD[0:1]
D[n]D[n-1]
tDH D[n+1]
t64CY
t64L
t64H
tDS
tDC
Figure 3 DSD Audio Timing - Normal Mode
Figure 4 DSD Audio Timing - Phase Modulated Mode
Test Conditions
DVDD = 3.3V, GND = 0V, TA = +25oC, fs = 44.1kHz, DSDCLK64 = 64fs unless otherwise stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Audio Data Input Timing Information
DSDCLK64 cycle time t64CY 354.3 ns
DSDCLK64 pulse width high t64H 140 ns
DSDCLK64 pulse width low t64L 140 ns
DSD[0:1] set-up time to
DSDCLK64 rising edge
tDSN 20 ns
DSD[0:1] hold time from
DSDCLK64 rising edge
tDHN 20 ns
Difference in edge timing of
DSD[0:1] to DSDCLK64
tDC -10 10 ns
Table 3 DSD Audio Interface Timing Requirements
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CONTROL INTERFACE TIMING – 3-WIRE MODE
Figure 5 Control Interface Timing - 3-Wire Serial Control Mode
Test Conditions
DVDD = 3.3V, GND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
SCLK rising edge to LATCH
rising edge
tSCS 40 ns
SCLK pulse cycle time tSCY 80 ns
SCLK pulse width low tSCL 32 ns
SCLK pulse width high tSCH 32 ns
SDIN to SCLK set-up time tDSU 20 ns
SCLK to SDIN hold time tDHO 20 ns
LATCH pulse width low tCSL 20 ns
LATCH pulse width high tCSH 20 ns
LATCH rising to SCLK rising tCSS 20 ns
Table 4 Control Interface Timing – 3-Wire Serial Control Mode
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CONTROL INTERFACE TIMING – 2-WIRE MODE
Figure 6 Control Interface Timing - 2-Wire Serial Control Mode
Test Conditions
DVDD = 3.3V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER SYMBOL MIN TYP MAX UNIT
SCLK Frequency 0 5 MHz
SCLK Low Pulse-Width tSCL 80 ns
SCLK High Pulse-Width tSCH 80 us
Hold Time (Start Condition) tHOL 600 ns
Setup Time (Start Condition) tCSE 600 ns
Data Setup Time tDSU 100 ns
SDIN, SCLK Rise Time tRIS 300 ns
SDIN, SCLK Fall Time tFAL 300 ns
Setup Time (Stop Condition) tCSS 600 ns
Data Hold Time tDHO 900 ns
Max Pulse width of spikes that will be suppressed tPS 4 6 ns
Table 5 Control Interface Timing – 2-wire Serial Control Mode
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INTERNAL POWER ON RESET CIRCUIT
The WM8741 includes two internal Power On Reset (POR) circuits which are used to reset the digital
logic into a default state after power up and to allow the analogue circuits to power-up silently.
The digital POR circuit is powered from DVDD. This circuit monitors DVDD and asserts the internal
digital reset if DVDD are below the minimum DVDD threshold which will allow the digital logic to
function.
The analogue POR circuit is powered from AVDD. The circuit monitors AVDD, tri-stating the DAC
outputs and isolating the internal reference resistor strings from AVDDL and AVDDR until there is
sufficient AVDD voltage to allow the analogue DAC stages to function correctly.
Figure 7 AVDD Power up Sequence
Test Conditions
AVDD = 5V, AGND = 0V, TA = +25oC, TA_max = +125oC, TA_min = -25oC, AVDDmax = 5.5V, AVDDmin = 4.5V
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Power Supply Input Timing Information
AVDD level to POR rising
edge (AVDD rising)
Vpor_hi Measured from AGND 2.00 V
AVDD level to POR falling
edge (AVDD falling)
Vpor_lo Measured from AGND 1.84 V
Table 6 Analogue POR Timing
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Figure 8 DVDD Power up Sequence
Test Conditions
DVDD = 3.3V, DGND = 0V, TA = +25oC, TA_max = +125oC, TA_min = -25oC, DVDDmax = 3.6V, DVDDmin = 3.0V
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Power Supply Input Timing Information
DVDD level to POR rising
edge (DVDD rising)
Vpor_hi Measured from DGND 1.86 V
DVDD level to POR falling
edge (DVDD falling)
Vpor_lo Measured from DGND 1.83 V
Table 7 Digital POR Timing
In a real application the designer is unlikely to have control of the relative power up sequence of
AVDD and DVDD. The POR circuit ensures a reasonable delay between applying power to the
device and Device Ready.
Figure 7 and Figure 8 show typical power up scenarios in a real system. DVDD must be established
before the device can be written to. Any writes to the device before device ready will be ignored.
Note: DVDD must be established before the MCLK is started. This will ensure all synchronisation
circuitry within the device is fully initialised and ready.
AVDD must be established before the device will output any signal. Whilst the device will output
signal as soon as the Internal Analogue PORB indicates device ready, normal operation is not
possible until the VMID pin has reached the midrail voltage.
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DEVICE DESCRIPTION
INTRODUCTION
The WM8741 is an ultra high performance DAC designed for digital audio applications. Its range of
features makes it ideally suited for use in professional recording environments, CD/DVD players, AV
receivers and other high-end consumer audio equipment.
The WM8741 is a complete differential stereo audio digital-to-analogue converter. The system
includes a dithered digital interpolation filter, fine resolution volume control and digital de-emphasis,
followed by a multi-bit sigma delta modulator and switched capacitor multi-bit stage with differential
voltage outputs. The device supports both PCM and DSD digital audio input formats.
The WM8741 includes a configurable digital audio interface support for a 3-wire and 2-wire serial
control interface, and a hardware control interface. The software control interface may be
asynchronous to the audio data interface; in which case control data will be re-synchronised to the
audio processing internally. It is fully compatible with, and an ideal partner for, a range of industry
standard microprocessors, controllers and DSPs.
Uniquely, the WM8741 has a large range of high performance low latency advanced digital filters.
The full range of filters is selectable in software mode, and a limited range of filters are available
under hardware control. The filters allow users the flexibility to choose characteristics to match their
group delay, phase and latency requirements.
Operation using a master clock of 128fs, 192fs, 256fs, 384fs, 512fs or 768fs is supported. Sample
rates (fs) from 32kHz to 192kHz are allowed, provided the appropriate master clock is input (see
Table 11 for details).
In normal PCM mode, the audio data interface supports right justified, left justified and I2S interface
formats along with a highly flexible DSP serial port interface.
There are two DSD modes. In DSD Direct mode, the datastream is subjected to the minimum
possible processing steps between input and output. In DSD Plus mode, the datastream is converted
to PCM and filtered to allow reduction of out of band components. This step also provides additional
benefits in allowing access to other PCM features such as volume control and advanced digital
filtering.
The device is packaged in a small 28-lead SSOP.
CLOCKING SCHEMES
In a typical digital audio system there is only one central clock source producing a reference clock to
which all audio data processing is synchronised. This clock is often referred to as the audio system’s
Master Clock. The external master system clock can be applied directly through the MCLK input pin
with no software configuration necessary for sample rate selection.
MCLK is used to derive clocks for the DAC path in PCM mode. The DAC path consists of DAC
sampling clock, DAC digital filter clock and DAC digital audio interface timing. In a system where
there are a number of possible sources for the reference clock it is recommended that the clock
source with the lowest jitter be used to optimise the performance of the DAC.
CONTROL INTERFACE
The WM8741 supports 2-wire and 3-wire serial control, and hardware control. Selection of control
mode is made by controlling the state of the MODE pin.
PIN NAME DESCRIPTION
24 MODE/
LRSEL
0 = Hardware control mode
1 = 3-wire serial control mode
Z = 2-wire serial control mode
Table 8 Control Mode Configuration
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SOFTWARE CONTROL INTERFACE
The software control interface may be operated using a 2-wire or 3-wire (SPI-compatible) serial
interface. When operating under serial control, hardware configuration pins are ignored.
Note: DIFFHW will override all other pins, forcing the device into hardware control mode and
differential mono mode.
3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE
Every rising edge of SCLK clocks in one bit of data on SDIN. A rising edge on CSB latches a
complete control word consisting of 16 bits. The 3-wire interface protocol is shown in Figure 9.
Figure 9 3-wire Serial Interface Protocol
Notes:
1. A[6:0] are Control Address Bits
2. D[7:0] are Control Data Bits
3. D[8] is always set to zero
3-WIRE CONTROL INTERFACE DAISY CHAINING
In daisy chaining mode, SDOUT (pin 25) outputs control data sampled on SDIN with a delay of 16
SCLK cycles. This data signal can be used to control another WM8741 in a daisy chain circuit as
shown in Figure 10.
DAC #1 DAC #3DAC #2
SDIN
SCLK
CSB
SDOUT
SDOUT
SDIN
CSB
SCLK
SDIN
CSB
SCLK
SDIN
CSB
SCLK
Figure 10 Control Interface Daisy Chaining Setup
To configure devices into daisy chain mode the CSB signal should be driven low while there is a
register write to set register bit SDOUT=1. CSB should then be driven high, this sets the first device
in daisy chain mode. CSB should then be driven low again while register bit SDOUT is set high.
Setting CSB high again will cause the first register write to be output to the second device from the
SDOUT pin, this sets the second device into daisy chain mode. This method must be repeated for
the number of devices in the chain until they are all set into daisy chain mode. Figure 11 shows the
protocol for configuring the first two devices in the daisy chain.
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Figure 11 Initial Setup of Two WM8741 Devices into Control Interface Daisy Chain Mode
To write to a single device in the chain a complete sequence needs to be written to all the devices.
Devices that do not require a register change must also be written to. The user can choose to write
either the same data as the previous write, or write all 1s for the register address and data. All 1s will
result in writing to a non-existent register, address 7Fh, preserving the current register settings.
Figure 12 shows an example of how to access three WM8741 devices (the devices have all
previously been configured in daisy chain mode):
Figure 12 Daisy Chain Control Interface Example for Three WM8741 Devices
To ensure that only valid data is written to the devices in daisy chain mode, a pull up resistor is used
in SDOUT. When connected to the SDIN pin of the next device in the chain, this results in all ones
being written to the control interface of that device until the correct daisy chain data is written and
latched.
Serial daisy chaining is available only when using 3-wire serial control mode. It is not available in 2-
wire serial control mode or hardware control mode.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R8
Mode Control 2
08h
5 SDOUT 0 3 wire Serial Interface Daisy Chaining
0 = No Output
1 = Output on pin 25.
Table 9 Control Interface Daisy Chaining Selection
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2-WIRE SERIAL CONTROL MODE
The WM8741 supports software control via a 2-wire serial bus. Many devices can be controlled by
the same bus, and each device has a unique 7-bit address (this is not the same as the 7-bit address
of each register in the WM8741).
The WM8741 operates as a slave device on the 2-wire control bus. The controller indicates the start
of data transfer with a high to low transition on SDIN while SCLK remains high. This indicates that a
device address and data will follow. All devices on the 2-wire bus respond to the start condition and
shift in the next eight bits on SDIN (7-bit address + Read/Write bit, MSB first). If the device address
received matches the address of the WM8741 and the R/W bit is ‘0’, indicating a write, then the
WM8741 responds by pulling SDIN low on the next clock pulse (ACK). If the address is not
recognised or the R/W bit is ‘1’, the WM8741 returns to the idle condition and wait for a new start
condition and valid address.
Once the WM8741 has acknowledged a correct address, the controller sends the first byte of control
data (B15 to B8, i.e. the WM8741 register address plus the first bit of register data). The WM8741
then acknowledges the first data byte by pulling SDIN low for one clock pulse. The controller then
sends the second byte of control data (B7 to B0, i.e. the remaining 8 bits of register data), and the
WM8741 acknowledges again by pulling SDIN low.
The transfer of data is complete when there is a low to high transition on SDIN while SCLK is high.
After receiving a complete address and data sequence the WM8741 returns to the idle state and
waits for another start condition. If a start or stop condition is detected out of sequence at any point
during data transfer (i.e. SDIN changes while SCLK is high), the device reverts to the idle condition.
Figure 13 2-wire Serial Control Interface
The WM8741 device address can be configured between two options. This is selected by the
SADDR pin.
PIN NAME DESCRIPTION
28 CSB/
SADDR/I2S
0 = 2-wire address 0011010
1 = 2-wire address 0011011
Table 10 2-wire Serial Control Mode Address Selection
DIGITAL AUDIO INTERFACE
PCM MODE
There are a number of valid PCM data input modes. Two channel and one channel differential mono
modes can be selected by serial or hardware control. It is also possible to bypass the WM8741 digital
filters and apply a signal at a rate 8fs (where fs is the sampling rate) directly to the switched capacitor
stage..
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PCM DIGITAL AUDIO INTERFACE
Audio data is applied to the DAC system via the Digital Audio Interface. Five popular interface
formats are supported:
Left Justified mode
Right Justified mode
I
2S mode
DSP mode A
DSP mode B
All five formats require the MSB to be transmitted first, and support word lengths of 16, 20, 24 and 32
bits, with the exception that 32 bit data is not supported in right justified mode. DIN and LRCLK may
be configured to be sampled on the rising or falling edge of BCLK by adjusting register bits LRP and
BCP.
In left justified, right justified and I2S audio interface modes, the digital audio interface receives data
on the DIN input pin. Stereo audio data is time multiplexed on DIN, with LRCLK indicating whether
the left or right channel is present. LRCLK is also used as a timing reference to indicate the
beginning or end of the data words.
The minimum number of BCLK periods per LRCLK period is two times the selected word length.
LRCLK must be high for a period equal to the minimum number of BCLK periods, and low for a
minimum of the same period. Any mark-to-space ratio on LRCLK is acceptable provided the above
requirements are met.
The WM8741 will automatically detect when data with a LRCLK period of exactly 32 BCLKs is
received, and select 16-bit mode. This overrides any previously programmed word length. The
operating word length will revert to a programmed value only if a LRCLK period other than 32 BCLKs
is detected.
In DSP mode A or DSP mode B, the data is time multiplexed onto DIN. LRCLK is used as a frame
sync signal to identify the MSB of the first word. The minimum number of BCLKs per LRCLK period is
two times the selected word length. Any mark to space ratio is acceptable on LRCLK provided the
rising edge is correctly positioned.
LEFT JUSTIFIED MODE
In left justified mode, the MSB is sampled on the first rising edge of BCLK following a LRCLK
transition. LRCLK is high during the left data word and low during the right data word.
Figure 14 Left Justified Mode Timing Diagram
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RIGHT JUSTIFIED MODE
In right justified mode, the LSB is sampled on the rising edge of BCLK preceding a LRCLK transition.
LRCLK is high during the left data word and low during the right data word.
Figure 15 Right Justified Mode Timing Diagram
I2S MODE
In I2S mode, the MSB is sampled on the second rising edge of BCLK following a LRCLK transition.
LRCLK is low during the left data word and high during the right data word.
Figure 16 I2S Mode Timing Diagram
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DSP MODE A
In DSP mode A, the first bit is sampled on the BCLK rising edge following the one that detects a low
to high transition on LRCLK. No BCLK edges are allowed between the data words. The word order
is DIN left, DIN right.
Figure 17 DSP Mode A Timing Diagram
DSP MODE B
In DSP mode B, the first bit is sampled on the BCLK rising edge, which detects a low to high
transition on LRCLK. No BCLK edges are allowed between the data words. The word order is DIN
left, DIN right.
Figure 18 DSP Mode B Timing Diagram
PCM MODE SAMPLING RATES
The WM8741 supports master clock rates of 128fs to 768fs, where fs is the audio sampling frequency
(LRCLK), typically 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz.
The WM8741 has a master clock detection circuit that automatically determines the relationship
between the master clock frequency and the sampling rate. The master clock should be
synchronised with LRCLK, although the WM8741 is tolerant of phase differences or jitter on this
clock.
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SAMPLING
RATE
(LRCLK)
MASTER CLOCK (MCLK) FREQUENCY (MHZ)
128fs 192fs 256fs 384fs 512fs 768fs
32kHz Unavailable Unavailable 8.192 12.288 16.384 24.576
44.1kHz Unavailable Unavailable 11.2896 16.9344 22.5792 33.8688
48kHz Unavailable Unavailable 12.288 18.432 24.576 36.864
88.2kHz 11.2896 16.9344 22.5792 33.8688 Unavailable Unavailable
96kHz 12.288 18.432 24.576 36.864 Unavailable Unavailable
176.4kHz 22.5792 33.8688 Unavailable Unavailable Unavailable Unavailable
192kHz 24.576 36.864 Unavailable Unavailable Unavailable Unavailable
Table 11 Typical Relationships between Master Clock Frequency and Sampling Rate in Normal
PCM Mode
8FS MODE
Operation in 8FS mode requires that audio data for left and right channels is input separately on two
pins. DINR (pin 4) is the input for right channel data and DINL (pin 2) is the input for left channel
data. Hardware control of the device is not available.
The data can be input in two formats (left or right justified), selectable by register FMT[1:0], and two
word lengths (20 or 24 bit), selectable by register IWL[1:0]. In both modes the data is clocked into the
WM8741 MSB first.
For left justified data the word start is identified by the falling edge of LRCLK. The data is clocked in
on the next 20/24 BCLK rising edges. This format is compatible with industry-standard DSPs and
decoders such as the PMD100.
Figure 19 8FS Mode Left Justified Timing Requirements
For right justified mode, the data is justified to the rising edge of LRCLK and the data is clocked in on
the preceding 20/24 BCLK rising edges before the LRCLK rising edge. This format is compatible with
industry standard DSPs and decoders such as the DF1704 or SM5842.
Figure 20 8FS Mode Right Justified Timing Requirements
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In both modes the polarity of LRCLK can be switched using register bit LRP.
8FS MODE SAMPLING RATES
Since the data rate in 8FS mode is much faster than in standard PCM mode, there are restrictions on
the MCLK rate that can be used. Specifically, only 512fs and 768fs modes are permitted restricting
the sample rate to a maximum of 8x48kHz. The master clock should be synchronised with LRCLK,
although the WM8741 is tolerant of phase differences or jitter on this clock.
Unlike in normal PCM mode, the master clock detection circuit does not operate in 8FS mode. The
rate must be manually programmed using the control interface.
SAMPLING
RATE
LRCLK
FREQUENCY
(kHz)
MASTER CLOCK (MCLK)
FREQUENCY (MHz)
fs 8fs 512fs 768fs
32kHz 256 16.384 24.576
44.1kHz 352.8 22.5792 33.8688
48kHz 384 24.576 36.864
Table 12 Typical Relationships between Master Clock Frequency and Sampling Rate in 8FS
Mode
AUDIO INTERFACE DAISY CHAINING
In daisy chain mode the DOUT pin outputs the audio data received on the DIN pin but delayed by two
times the input word length. When this output is connected to the DIN pin of the next device in the
chain, each WM8741 device will simultaneously sample different channel data in the same LRCLK
period. Daisy chaining is only available in DSP audio interface mode and is limited by a maximum
BCLK frequency of 24.576MHz.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R8
Mode Control 2
08h
4 DOUT 0 Daisy Chaining Multiple devices –
multichannel off one PCM feed.
0 = No Output
1 = Output on pin 23.
Table 13 Daisy Chaining Audio Data Output Control
The following diagram illustrates timing for a daisy chain with 2 WM8741 devices.
Figure 21 Audio Interface Daisy Chaining Timing
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DSD MODE
The WM8741 supports DSD input bitstreams at 64x the oversampling rate. The data is supplied at a
rate of 64 bits per normal word clock. In DSD, no word clock is provided.
The WM8741 supports two channels of bitstream or DSD audio. Data bitstreams and the 64fs clock
are supplied to pins 1, 22 and 3 respectively. The MODESEL[1:0] register bits control whether the
device operates in DSD direct, DSD plus or PCM modes.
DSD DIRECT
In DSD Direct mode the internal digital filters are bypassed, the input bitstream data is subjected to
the minimal possible processing and is applied directly to the switched capacitor stage of the DAC
system. Using this mode provides the purest possible representation of a DSD stream.
It is normally desirable to use an external analogue post-DAC analogue filter to combine the
differential outputs of the DAC and remove high frequency energy from the output. This is particularly
important in the case of DSD operation due to the presence of high frequency energy which is a result
of the aggressive high order noise shaping used in the creation of the modulated DSD datastream.
DSD PLUS MODE
In DSD Plus mode the DSD data can be filtered in a similar manner to the data in the PCM path. The
DSD Plus filters are selected using register bits DSDFILT[1:0]. DSD Plus mode is not available under
hardware control.
Although DSD Plus mode requires that the bitstream is more heavily processed than DSD Direct, the
advantage is that DSD Plus mode reduces the high frequency energy which is a result of the
aggressive high order noise shaping used in the creation of the modulated DSD datastream. This
means that a less aggressive, lower order, analogue filter can be used at the output. Furthermore the
slew-rate requirements of the op-amps can be relaxed compared to DSD direct mode, due to the
reduction in high frequency energy.
DSD DIGITAL AUDIO INTERFACE
DSD audio data is input to the WM8741 via the DSD digital audio interface. Two interface formats
are supported:
Uni-phase
Bi-phase
To use this interface apply left data on input pin 1 (LRCLK/DSDL) and pin 22 (OSR/DSDR). A DSD
clock is also required, running at 64FS, and should be applied to pin 3 (BCLK/DSD64CLK).
Figure 22 Uni-phase DSD Mode Timing Diagram
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Figure 23 Bi-phase DSD Mode Timing Diagram
SOFTWARE CONTROL MODE
Software control allows access to all features of the WM8741. Selection of control mode is achieved
by configuring the state of MODE/LRSEL (pin 24):
PIN NAME DESCRIPTION
24 MODE/
LRSEL
0 = Hardware control mode
1 = 3-wire serial control mode
Z = 2-wire serial control mode
Table 14 Control Mode Configuration
DSD AND PCM MODE SWITCHING
The audio interface mode can be switched between DSD and PCM by writing MODESEL[1:0] in R7.
It is recommended that the chip is forced into a MUTE state before dynamically switching modes.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R7
Mode Control 1
07h
[1:0] MODESEL 00 DSD/PCM mode select :
00 = PCM mode
01 = Direct DSD Operation
10 = DSD plus mode
11 = Unused
Table 15 PCM/DSD Software Mode Selection
PCM DIGITAL AUDIO INTERFACE CONTROL REGISTERS
The PCM digital audio input format is configured by register bits FMT [1:0] and IWL[1:0]:
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
1:0 IWL[1:0] 10 Audio interface input word length
select
00 = 16-bit
01 = 20-bit
10 = 24-bit
11 = 32-bit
3:2 FMT[1:0] 10 Audio interface input format select
00 = Right justified
01 = Left justified
10 = I2S
11 = DSP
Table 16 Interface Format Controls
Note:
1. In all modes, the data is signed 2's complement. The WM8741 digital filters always input
24-bit data. If the interface is programmed into 32 bits, dither is applied according to
Table 37 before truncation to the internal wordlength.
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LRCLK POLARITY
In left justified, right justified or I2S modes, the LRP register bit controls the polarity of LRCLK. If this
bit is set high, the expected polarity of LRCLK will be the opposite of that shown in Figure 14, Figure
15 and Figure 16. If this feature is used as a means of swapping the left and right channels, a 1
sample phase difference will be introduced.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
4 LRP 0 LRCLK polarity select:
0 = normal LRCLK polarity
1 = inverted LRCLK polarity
Table 17 LRCLK Polarity Control
In DSP modes, the LRP register bit is used to select between DSP mode A and B (see Figure 17 and
Figure 18).
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
4 LRP 0 DSP format select:
0 = DSP mode A
1 = DSP mode B
Table 18 DSP Format Control
BCLK / DSDCLK64 POLARITY
In PCM mode, LRCLK and DIN are sampled on the rising edge of BCLK by default, and should ideally
change on the falling edge. Data sources which change LRCLK and DIN on the rising edge of BCLK
can be supported by setting the BCP register bit. Setting BCP to 1 inverts the polarity of BCLK to the
inverse of that shown in Figure 14, Figure 15, Figure 16, Figure 17 and Figure 18.
In DSD mode, DSDL and DSDR inputs are sampled a fixed delay after a falling 64fs clock edge.
When BCP is set in DSD mode, DSDL and DSDR are sampled a fixed delay after a rising 64fs clock
edge.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
5 BCP 0 BCLK / DSD64CLK polarity select:
0 = normal polarity
1 = inverted polarity
Table 19 BCLK Polarity Control
OVERSAMPLING RATE CONTROL
The user has control of the oversampling ratio of the WM8741, and can set to the device to operate in
low, medium or high rate modes. For correct operation of the digital filtering and other processing on
the WM8741, the user must ensure the correct value of OSR[1:0] is set at all times.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R7
Mode Control 1
07h
[6:5] OSR[1:0] 00 Oversampling Rate Selection
00 = Low rate (32/44.1/48kHz)
01 = Medium rate (96kHz)
10 = High rate (192kHz)
11 = Unused
Table 20 Oversampling Rate Control
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MCLK/LRCLK RATIO CONTROL (NORMAL PCM MODE)
The ratio of MCLK/LRCLK can be programmed directly or auto-detected.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R7
Mode Control 1
07h
[4:2] SR[3:0] 000 MCLK to LRCLK sampling rate ratio
control (Normal PCM Mode):
000 = auto detect sample rate
001 = 128fs
010 = 192fs
011 = 256fs
100 = 384fs
101 = 512fs
110 = 768fs
111 = reserved
Table 21 MCLK/LRCLK Ratio Control (Normal PCM Mode)
8FS MODE
8FS Mode allows the use of custom digital filters by bypassing the WM8741 internal digital filters.
When MODE8X is set, the PCM data input to the WM8741 is applied only to the digital volume control
and then the analogue section of the DAC system, bypassing the digital filters.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R7
Format Control
07h
7 MODE8X 0 8FS mode select:
0 = Normal operation
1 = 8FS mode (digital filters
bypassed)
Table 22 8FS Mode Control
MCLK/LRCLK RATIO CONTROL (8FS MODE)
In 8FS mode the choice of clock ratios and sampling rates is limited – see Table 12 for details.
Autodetect of MCLK/LRCLK ratio is not available in 8FS mode and must be set manually by the user
for correct operation.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R7
Mode Control 1
07h
[4:2] SR[2:0] 000 MCLK to LRCLK sampling rate ratio
control (8FS Mode):
000 = reserved
001 = 512fs
010 = 768fs
011 to 111 = reserved
Table 23 MCLK/LRCLK Ratio Control (8FS Mode)
ATTENUATION CONTROL
Each DAC channel can be attenuated digitally before being applied to the digital filter. Attenuation is
set to 0dB by default but can be set between 0dB and -127.5dB in 0.125dB steps using the ten
attenuation control bits LAT[4:0], LAT[9:5], RAT[4:0] and RAT[9:5].
All attenuation registers are double latched allowing new values to be pre-latched to both channels
before being updated synchronously. Setting the UPDATE bit on any attenuation write will cause all
pre-latched values to be immediately applied to the DAC channels.
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REGISTER
ADDRESS
BITS LABEL DEFAULT DESCRIPTION
R0
DACLLSB
Attenuation
00h
[4:0] LAT[4:0] 00 (0dB) LSBs of attenuation data for left channel in 0.125dB steps. See
Table 25 for details.
5 UPDATE 0
Attenuation data load control for left channel.
0 = Store LAT[4:0] value but don’t update
1 = Store LAT[4:0] and update attenuation on registers 0-3
R1
DACLMSB
Attenuation
01h
[4:0] LAT[9:5] 00 (0dB) MSBs of attenuation data for left channel in 4dB steps. See Table
25 for details.
5 UPDATE 0
Attenuation data load control for left channel.
0 = Store LAT[9:5] value but don’t update
1 = Store LAT[9:5] and update attenuation on registers 0-3
R2
DACRLSB
Attenuation
02h
[4:0] RAT[4:0] 00 (0dB) LSBs of attenuation data for right channel in 0.125dB steps. See
Table 25 for details.
5 UPDATE 0 Attenuation data load control for right channel.
0 = Store RAT[4:0] value but don’t update
1 = Store RAT[4:0] and update attenuation on registers 0-3
R3
DACRMSB
Attenuation
03h
[4:0] RAT[9:5] 00 (0dB) MSBs of attenuation data for right channel in 4dB step. See Table
25 for details.
5 UPDATE 0 Attenuation data load control for right channel.
0 = Store RAT[9:5] value but don’t update
1 = Store RAT[9:5] and update attenuation on registers 0-3
Table 24 Attenuation Control
Note:
1. The UPDATE bit is not latched. If UPDATE=0, the attenuation value will be written to the pre-latch but not applied to
the relevant DAC. If UPDATE=1, all pre-latched values and the current value being written will be applied on the next
input sample.
DAC OUTPUT ATTENUATION
Registers LAT[9:0] and RAT[9:0] control the left and right channel attenuation. Table 25 shows how
the attenuation levels are configured by the 10-bit words.
L/RAT[9:0] ATTENUATION LEVEL
000(hex) 0dB
001(hex) -0.125dB
: :
: :
: :
3FE(hex) -127.75dB
3FF(hex) -dB (mute)
Table 25 Attenuation Control Levels
ATTENUATION CONTROL MODE
Setting the ATC register bit causes the left channel attenuation settings to be applied to both left and
right channel DACs from the next audio input sample. No update to the attenuation registers is
required for ATC to take effect. Right channels register settings are preserved regardless of the
status of ATC.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
2 ATC 0 Attenuator Control Mode:
0 = Right channels use Right
attenuation
1 = Right Channels use Left
Attenuation
Table 26 Attenuator Control Mode
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VOLUME RAMP MODE
There are two ways to change the volume in the WM8741, controlled by VOL_RAMP. When
VOL_RAMP=0, the volume changes in a single step from the current volume setting to the new
volume when an update is applied to the gain control registers. When VOL_RAMP=1, the volume is
automatically ramped from the current volume setting to the new volume setting when an update is
applied to the volume control registers. The speed at which this happens is dependant on the sample
rate as shown in Table 27 below:
SAMPLE RATE (kHz) RAMP RATE (ms/dB)
32 1.000
44.1 0.726
48 0.667
88.2 0.726
96 0.667
176.4 0.726
196 0.667
Table 27 Volume Ramp Rates
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
0 VOL_
RAMP
0 Volume ramp mode control:
0 = Apply volume change in a single
step.
1 = Ramp between current volume
setting and new volume setting.
Table 28 Volume Ramp Control
ANTI-CLIPPING DIGITAL ATTENUATION MODE
Audio material is regularly recorded up to 0dB level and heavily compressed. This may cause
clipping and occasional distortion when the digital media is applied to a DAC. In order to prevent this
in the WM8741, an anti-clipping mode is provided, which attenuates the digital signal by 2dB as it is
processed through the digital filters.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
1 ATT2DB 0 Anti-clipping mode control:
0 = Off, 0dB attenuation
1 = On, 2dB attenuation applied
Table 29 Anti-Clipping Digital Attenuation Control
DSD PLUS GAIN CONTROL
The gain in the DSD Plus data path can be adjusted. The default setting provides a 1.4Vrms
differential output level.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R8
Mode Control 2
08h
6 DSD_
GAIN
0 DSD Plus gain control:
0 = Low gain, 1.4Vrms differential
output level
1 = High gain, 2.0Vrms differential
output level
Table 30 DSD Plus Gain Control
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MUTE MODES
0.000 0.020 0.040 0.060 0.080 0.100 0.120 0.140
Time (s)
Figure 24 Application and Release of Soft Mute
Figure 24 shows the application and release of SOFTMUTE for a full amplitude sinusoid being played
at 48kHz sampling rate. When SOFTMUTE (lower trace) is asserted, the WM8741 output (upper
trace) begins to decay exponentially from the DC level of the last input sample. The output decays
towards VMID in 1022x4/fs seconds. When SOFTMUTE is de-asserted, the signal gain will return to its
previous value.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
PCM Control
04h
3 SOFTMUTE 0 Soft mute select
0 = Normal operation
1 = Soft mute both channels
Table 31 Soft Mute Control
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ZERO FLAG OUTPUT
The WM8741 has one zero flag output pin, ZFLAG (pin 21). The zero flag feature is only valid for
PCM data.
The WM8741 asserts Logic 1 on the ZFLAG pin when a sequence of more than 1024 zeros is input to
the chip. The default value is a logical AND of both left and right channels. Under software control,
the user can also set the zero flag pin to respond to either the left channel OR the right channel.
The zero flag pin can be used to control external muting circuits if required.
REGISTER
ADDRESS
BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
6:5 ZEROFLR
[1:0]
00 Zero flag output:
00 = Pin assigned to logical AND of
LEFT and RIGHT channels
01 = Pin assigned to LEFT channel
10 = Pin assigned to RIGHT
channel
11 = ZFLAG disabled
Table 32 Zero Flag Output
ZFLAG FORCE HIGH CONTROL
It is possible to force the ZFLAG pin to Logic 1 by setting ZFLAG_HI=1 in R7. This is useful in
situations where an application processor may require manual control of an external mute circuit.
Setting ZFLAG_HI=0 will allow the ZFLAG pin to function as defined by ZFLAGLR[1:0].
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R6
Mode Control 1
06h
7 ZFLAG_HI 0 ZFLAG Force High Control
0 = Normal operation
1 = Output Logic 1
Table 33 ZFLAG Force High Control
INFINITE ZERO DETECT
The IZD register configures the operation of the WM8741 analogue mute in conjunction with the zero
flag feature. Table 20 shows the interdependency of the MUTEB pin, the IZD register and the zero
flag.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
4 IZD 0 IZD control of analogue mute:
0 = Never analogue mute
1 = Analogue mute when ZFLAG
set
Table 20 Infinite Zero Detect Control
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MUTEB ZFLAG
DAC
DINL
DINR
ZDET
ANA
L&R
SOFT
L&R
DSD Direct
Infinite
Zero
Detect
Figure 25 Software Control Mode MUTEB and ZFLAG Configuration
DE-EMPHASIS
Setting the DEEMPH[1:0] register bits enables de-emphasis support in the WM8741 digital filters.
There are three de-emphasis filters, one each for sampling rates of 32kHz, 44.1kHz and 48kHz.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R6
Filter Control
06h
[6:5] DEEMPH
[1:0]
00 De-emphasis mode select:
00 = De-emphasis Off
01 = De-emphasis 32kHz
10 = De-emphasis 44.1kHz
11 = De-emphasis 48kHz
Table 34 De-emphasis Control
OUTPUT PHASE REVERSAL
The REV register bit controls the phase of the output signal. Setting the REV bit causes the phase of
the output signal to be inverted.
Note: The REV bit can only be used in stereo mode. When in differential mono mode, the REV bit
must remain set as 0.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
6 REV 0 Analogue output phase control:
0 = Normal
1 = Inverted
Table 35 Output Phase Control
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DIFFERENTIAL MONO MODE
DIFF[1:0] sets the required differential output mode; normal stereo, reversed stereo, mono left or
mono right, as shown in Table 36.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R8
Mode Control 2
08h
[3:2] DIFF[1:0] 00 00 = Stereo
10 = Stereo reverse (left and right
channels swapped)
01 = Mono left – differential outputs
VOUTLP (17) is left channel.
VOUTLN (16) is left channel
inverted.
VOUTRP (12) is left channel
inverted.
VOUTRN (13) is left channel.
11 = Mono right – differential outputs.
VOUTLP (17) is right channel
inverted.
VOUTLN (16) is right channel.
VOUTRP (12) is right channel.
VOUTRN (13) is right channel
inverted.
Table 36 Differential Output Modes
Using these controls a pair of WM8741 devices may be used to build a dual differential stereo
implementation with higher performance and differential output.
DITHER
Dither is applied whenever internal truncation occurs. It is also used when a 32 bit input word is
applied to the DAC prior to truncation to the internal wordlength. Three types of dither can be
selected to allow the sound quality if the device to be optimised.
TDF has a triangular probability density function and causes zero noise modulation i.e. the
quantisation noise is invariant to the changes in the signal level. This mode is recommended and is
selected by default.
RPDF has a rectangular probability density function and may cause noise modulation.
HPDF has a triangular probability density function with a high pass characteristic, which has a lower
noise at low frequencies at the expense of raised noise levels at higher frequencies.
Alternatively the dither can be disabled.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R8
Mode Control 2
08h
[1:0] DITHER
[1:0]
10 Digital filter dither mode select:
00 = dither off
01 = RPDF dither applied in Digital
filter
10 = TPDF dither applied in Digital
filter
11 = HPDF dither applied in Digital
filter
Note: DITHER[1:0] applies only to the
dither mode in the Digital filter.
Table 37 Dither Control
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NORMAL PCM MODE DIGITAL FILTER SELECTION
The WM8741 has a number of advanced digital filters that can be selected in all PCM operation
modes (with the exception of 8FS mode).
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R6
Filter Control
06h
[2:0] FIRSEL 000 Selects FIR1 filter response
000 = Response 1
001 = Response 2
010 = Response 3
011 = Response 4
100 = Response 5
Table 38 PCM Advanced Digital Filter Selection
Five digital filters are available for selection in each of the three OSR modes (low, medium and high
rate) as selected by the OSR bit described in Table 20. It is recommended that the device is muted
before the filter response is changed to prevent noise as the filters are reset from appearing on the
outputs. A summary of the filter characteristics is given in Table 39 below:
OSR RESPONSE NOTES
Low 1 Linear phase half-band filter for backward compatibility
2 Minimum phase ‘soft-knee’ filter
3 Minimum phase half-band filter
4 Linear phase apodising filter
5 Minimum phase apodising filter
Medium 1 Linear phase ‘soft-knee’ filter
2 Minimum phase ‘soft-knee’ filter
3 Linear phase ‘brickwall’ filter
4 Minimum phase apodising filter
5 Linear phase apodising filter
High 1 Linear phase ‘soft-knee’ filter
2 Minimum phase ‘soft-knee’ filter
3 Linear phase ‘brickwall’ filter
4 Minimum phase apodising filter
5 Linear phase apodising filter
Table 39 PCM Digital Filter Summary
For full details of the filter characteristics available in normal PCM mode, please see Table 64 to
Table 66 and Figure 28 to Figure 57.
8FS MODE DIGITAL FILTER
In 8FS mode, the majority of the internal filters are bypassed. In this mode, the data is filtered using
only the filter characteristic described by Table 67 and shown in Figure 58 and Figure 59.
DSD PLUS FILTER SELECTION
The WM8741 has a number of compensation filters that can be selected in DSD Plus mode.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R6
Filter Control
06h
[4:3] DSDFILT
[1:0]
00 Selects Compensation Filter
response
00 = Response 1
01 = Response 2
10 = Response 3
11 = Response 4
Table 40 DSD Plus Digital Filter Selection
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It is recommended that the device is muted before the filter response is changed to prevent noise as
the filters are reset from appearing on the outputs.
Full details of these filters are described in Table 68 and Figure 60 to Figure 67.
DSD DIRECT DIGITAL FILTERS
The DSD Direct filters have been designed to provide the minimal of processing to the data with no
decimation, re-quantisation or noise-shaping, in order to preserve the signal integrity as much as
possible. As a result the filters have a wide bandwidth and a very gradual attenuation. It is
recommended that whichever DSD Direct filter is chosen it is augmented by analogue post-DAC
filtering in order to adhere to the Scarlet-Book SACD standard.
There are a total of four DSD Direct filter responses available, controlled by two register bits as
described in Table 41 below:
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R32
Additional Control 1
20h
0 DSD_NO_
NOTCH
0 DSD Direct 8fs Notch Filter
0: Enable 8fs notch filter
1: Disable 8fs notch filter
1 DSD_
LEVEL
1 DSD Direct Filter Gain
0: High gain
1: Low gain
Table 41 DSD Direct Digital Filter Selection
DSD MUTE CONTROL
In DSD Direct mode, an analogue mute can be applied at the output of the DAC. This is controlled by
register bit AMUTE.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R4
Volume Control
04h
7 AMUTE 0 DSD Direct mute control:
0 = mute off
1 = mute on
Table 42 DSD Analogue Mute Control
POWER SAVING STANDBY CONTROL
Setting the PWDN register bit immediately connects all outputs to VMID and resets the digital sections
of the DAC system including the DLL, the audio interface and the DSP. Input data samples are not
preserved, but all control register settings are maintained. When PWDN is cleared the WM8741 will
repeat its power-on initialisation sequence.
REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION
R5
Format Control
05h
7 PWDN 0 Power Down Mode Select:
0 = Normal Mode
1 = Power Down Mode
Table 43 Powerdown Control
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HARDWARE CONTROL MODE
When the MODE pin is held ‘low’ the WM8741 is set to hardware control mode and a limited feature
set can be configured.
PIN NAME DESCRIPTION
24 MODE/
LRSEL
0 = Hardware control mode
1 = 3-wire serial control mode
Z = 2-wire serial control mode
Table 44 MODE/LRSEL Hardware Control Pin Function
DSD AND PCM MODE SWITCHING
The audio interface mode can be switched between DSD Direct and PCM by controlling the state of
pin DSD. It is recommended that the chip is forced into a MUTE state before dynamically switching
modes.
PIN NAME DESCRIPTION
27 SCLK/DSD 0 = PCM Mode
1 = DSD Direct Mode
Table 45 SCLK/DSD Hardware Control Pin Function
AUDIO INPUT FORMAT
Under hardware control, it is possible to select between four different modes of operation for the PCM
audio interface.
PIN NUMBER 28 23
DESCRIPTION
NAME CSB/SADDR/I2S IWO/DOUT
STATUS 0 0 16-bit right justified
0 1 24-bit right justified
1 0 24-bit left justified
1 1 24-bit I2S
Table 46 CSB/SADDR/I2S and IWO/DOUT Hardware Control Pin Function
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OVERSAMPLING RATE CONTROL
The user has control of the oversampling ratio of the WM8741, and can set to the device to operate in
low, medium or high rate modes. For optimum operation of the digital filtering and other processing
on the WM8741 in PCM hardware mode, the user must ensure the correct value of OSR is set at all
times. Table 47 shows the correct settings:
PIN NAME DESCRIPTION
22 OSR/DSDR Oversampling Rate Selection
0 = Low rate (32/44.1/48kHz)
Z = Medium rate (88.2/96kHz)
1 = High rate (176.4/192kHz)
Table 47 OSR/DSDR Hardware Control Pin Function
MUTE PIN
A soft mute can be applied to the WM8741 in the digital domain in all PCM. A logic low on the
MUTEB pin will cause the attenuation to ramp to infinite attenuation at a rate of 1022x(4/fs). Setting
MUTEB high will return the signal gain to its previous value. Figure 26 shows the soft mute
characteristic.
In DSD Direct mode the MUTEB pin controls the analogue mute in the DAC. This analogue mute is a
‘hard’ mute and is applied and released as soon as the MUTEB pin is toggled.
PIN NAME DESCRIPTION
25 MUTEB/
SDOUT
Mute control
0 = Mute on (no output)
1 = Mute off (normal operation
Table 48 MUTEB Hardware Control Pin Function
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
Time (s)
Figure 26 Hardware Control Mode Soft Mute Characteristic
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ZERO FLAG
In hardware control mode the ZFLAG pin asserts when 1024 consecutive zero samples are applied to
the left and right channels of the WM8741 when in PCM mode. In DSD mode, the ZFLAG has no
function.
In hardware mode there is no access to the infinite zero detect and so there is no automute function.
If this functionality is required, software mode must be used. Figure 27 shows the MUTEB and
ZFLAG configuration.
Figure 27 Hardware Control Mode MUTEB and ZFLAG Configuration
DE-EMPHASIS CONTROL AND ANTI-CLIPPING MODE
In hardware control mode, de-emphasis is supported with a maximum error of +1.5dB at a sampling
rate of 44.1kHz.
Audio material is regularly recorded up to 0dB level and heavily compressed. This causes clipping
and distortion when the digital media is applied to a DAC. In order to prevent this in the WM8741, an
anti-clipping mode is provided, which attenuates the digital signal by 2dB as it is processed through
the digital filters.
Under hardware control de-emphasis and the anti-clipping mode are only available when using PCM
mode.
PIN NAME DESCRIPTION
26 SDIN/
DEEMPH
Deemphasis Control
0 = De-emphasis off
1 = De-emphasis on
Z = Digital filter anti-clipping mode
Table 49 DEEMPH Hardware Control Pin Function
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DIGITAL FILTER SELECTION
The WM8741 includes a wide range of digital filters. A limited set of these can be selected in
hardware control mode as listed in Table 50. Full details of each digital filter response can be found
in section PCM Digital Filter Selection, from page 37.
PIN NAME DESCRIPTION
4 FSEL/
DINR
Digital filter selection
(32/44.1/48kHz):
0 = Response 1
1 = Response 5
Z = Response 4
Digital filter selection (88.2/96kHz
and 176.4/192kHz):
0 = Response 1
1 = Response 3
Z = Response 2
Table 50 FSEL/DINR Hardware Control Pin Function
There is no choice of digital filters in DSD Direct mode – only the very minimal filtering described in
Figure 72 and Figure 73 is available.
DIFFERENTIAL MONO MODE
If DIFFHW (pin 6) is held to Logic 1, hardware controlled differential mono mode is selected. This
overrides any other control pin or register bit. Differential mono mode allows the user to build a dual
differential stereo DAC implementation with higher performance and differential output. DIFFHW is
used in conjunction with MODE/LRSEL (pin 24) to define a ‘left’ or ‘right’ DAC as shown in Table 51.
PIN NUMBER 6 24
DESCRIPTION
NAME DIFFHW MODE/LRSEL
0 0 Hardware control (stereo)
0 Z 2-wire Software Control
0 1 3-wire software control)
1 0
Mono Left – differential outputs
VOUTLP = left channel
VOUTLN = left channel inverted
VOUTRP = left channel inverted
VOUTRN = left channel
1 1
Mono right – differential outputs
VOUTLP = right channel inverted
VOUTLN = right channel
VOUTRP = right channel
VOUTRN = right channel inverted
Table 51 DIFFHW and MODE/LRSEL Hardware Control Pin Functions
Differential mono mode is available for all PCM hardware controlled modes and DSD Direct hardware
mode.
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OVERVIEW OF FUNCTIONS
The WM8741 has many modes of operation, and certain restrictions on what functions are available
in which modes. Table 52 gives an overview of the functions available in hardware and software
control modes across all modes of operation:
SOFTWARE MODE HARDWARE MODE
FUNCTION NORMAL
PCM
8FS
MODE
DSD
PLUS
DSD
DIRECT
NORMAL
PCM
DSD
DIRECT
Selectable Digital Filters 5 4 4 3
De-emphasis Support
Adjustable DSP Dither
Differential Mono Mode
Digital Softmute
Analogue Mute
Zero Detect (ZFLAG)
Automute Function
Anti-Clipping Mode
Digital Attenuation
Powerdown Mode
Audio Interface Daisy Chain
3-wire Software Interface
Daisy Chain
Table 52 Comparison of Functions Available across Operating Modes
= function available
= function not available
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REGISTER MAP
Reg Name Addr Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default
0 DACLLSB
Attenuation 00h 0 0 0 UPDATELL LAT[4:0] 0x000
1 DACLMSB
Attenuation 01h 0 0 0 UPDATELM LAT[9:5] 0x000
2 DACRLSB
Attenuation 02h 0 0 0 UPDATERL RAT[4:0] 0x000
3 DACRMSB
Attenuation 03h 0 0 0 UPDATERM RAT[9:5] 0x000
4 Volume Control 04h 0 AMUTE ZEROFLR[1:0] IZD
SOFT
MUTE
ATC ATT2DB VOL_RAMP
0x000
5 Format Control 05h 0 PWDN REV BCP LRP FMT[1:0] IWL[1:0] 0x00A
6 Filter Control 06h 0 ZFLAG_HI DEEMPH[1:0] DSDFILT[1:0] FIRSEL[2:0] 0x000
7 Mode Control 1 07h 0 MODE8X OSR[1:0] SR[2:0] MODESEL[1:0] 0x000
8 Mode Control 2 08h 0 0 DSD_GAIN SDOUT DOUT DIFF[1:0] DITHER[1:0]
0x002
9 Software Reset 09h RESET 0x000
32 Additional
Control 1 20h 0 0 0 0 0 0 0 DSD_LEVEL
DSD_NO_
NOTCH
0x000
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REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R0
DACLLSB
Attenuation
00h
[4:0] LAT[4:0] 00 (0dB) LSBs of attenuation data for left channel in 0.125dB steps. See Table
25 for details.
5 UPDATE 0 Attenuation data load control for left channel.
0 = Store LAT[4:0] value but don’t update
1 = Store LAT[4:0] and update attenuation on registers 0-3
Table 53 R0 DACL LSB Attenuation Control Register
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R1
DACLMSB
Attenuation
01h
[4:0] LAT[9:5] 00 (0dB) MSBs of attenuation data for left channel in 4dB steps. See Table 25
for details.
5 UPDATE 0 Attenuation data load control for left channel.
0 = Store LAT[9:5] value but don’t update
1 = Store LAT[9:5] and update attenuation on registers 0-3
Table 54 R1 DACL MSB Attenuation Control Register
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R2
DACRLSB
Attenuation
02h
[4:0] RAT[4:0] 00 (0dB) LSBs of attenuation data for right channel in 0.125dB steps. See
Table 25 for details.
5 UPDATE 0 Attenuation data load control for right channel.
0 = Store RAT[4:0] value but don’t update
1 = Store RAT[4:0] and update attenuation on registers 0-3
Table 55 R2 DACR LSB Attenuation Control Register
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R3
DACRMSB
Attenuation
03h
[4:0] RAT[9:5] 00 (0dB) MSBs of attenuation data for right channel in 4dB step. See Table 25
for details.
5 UPDATE 0 Attenuation data load control for right channel.
0 = Store RAT[9:5] value but don’t update
1 = Store RAT[9:5] and update attenuation on registers 0-3
Table 56 R3 DACR MSB Attenuation Control Register
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REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R4
Volume
Control
04h
0 VOL_RAMP 0 Ramps volume from existing attenuation setting to new setting when
UPDATE applied.
0: Step volume change
1: Ramp volume change
1 ATT2DB 0 Anti-clipping mode control. Attenuates PCM gain path by 2 dB:
0: 0dB gain
1: -2dB gain
2 ATC 0 Attenuator Control Mode:
0 = Right channels use Right attenuation
1 = Right Channels use Left Attenuation
3 SOFTMUTE 0 Soft mute select
0: Normal Operation
1: Soft mute both channels
4 IZD 0 Enables infinite zero detect (detects 1024 zeros on input):
0 = Disable infinite zero detect
1 = Enable infinite zero detect
6:5 ZEROFLR
[1:0]
00 Zero flag output:
00 = Pin assigned to logical AND of LEFT and RIGHT channels
01 = Pin assigned to LEFT channel
10 = Pin assigned to RIGHT channel
11 = ZFLAG disabled
7 AMUTE 0 Applies analogue mute in DSD mode
0 = Normal operation
1 = Analogue mute applied
Table 57 R4 Volume Control Register
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REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R5
Format
Control
05h
[1:0] IWL[1:0] 10 Audio interface input word length.
00 = 16-bit
01 = 20-bit
10 = 24-bit
11 = 32-bit
[3:2] FMT[1:0] 10 Audio data format select.
00 = right justified mode
01 = left justified mode
10 = I2S mode
11 = DSP mode
4 LRP 0 Polarity select for LRCLK/DSP mode select.
0 = normal LRCLK polarity/DSP mode A
1 = inverted LRCLK polarity/DSP mode B
5 BCP 0 BCLK / DSD64CLK polarity select:
0 = normal polarity
1 = inverted polarity
6 REV 0 Analogue output phase control:
0 = Normal
1 = Inverted
7 PWDN 0 Power Down Mode Select:
0 = Normal Mode
1 = Power Down Mode
Table 58 R5 Format Control Register
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R6
Filter Control
06h
[2:0] FIRSEL 000 Select advanced digital filter response:
000 = Response 1
001 = Response 2
010 = Response 3
011 = Response 4
100 = Response 5
[4:3] DSDFILT 00 Select DSD compensation filter response:
00 = Response 1
01 = Response 2
10 = Response 3
11 = Response 4
[6:5] DEEMPH
[1:0]
00 De-emphasis mode select:
00 = De-emphasis Off
01 = De-emphasis 32kHz
10 = De-emphasis 44.1kHz
11 = De-emphasis 48kHz
7 ZFLAG_HI 0 ZFLAG Force High Control
0 = Normal operation
1 = Output Logic 1
Table 59 R6 Filter Control Register
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REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R7
Mode Control 1
07h
[1:0] MODESEL
[1:0]
00 DSD/PCM mode select.
00 = PCM mode
01 = DSD Direct mode
10 = DSD Plus mode
11 = Unused
[4:2] SR[3:0] 000 MCLK to LRCLK sampling rate ratio control:
000 = auto detect sample rate
001 = 128fs
010 = 192fs
011 = 256fs
100 = 384fs
101 = 512fs
110 = 768fs
[6:5] OSR[1:0] 00 Selects low, medium or high sample rate mode for filter selection
(equivalent to OSR pin functionality in Hardware Mode)
00 = Low rate (32/44.1/48kHz)
01 = Medium rate (96kHz)
10 = High rate (192kHz)
11 = Unused
7 MODE8X 0 8FS mode select:
0 = Normal operation
1 = 8FS mode (digital filters bypassed)
Table 60 R7 Mode Control Register 1
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R8
Mode Control 2
08h
[1:0] DITHER[1:0] 10 ALU dither mode select:
00 = dither off
01 = RPDF dither applied in ALU
10 = TPDF dither applied in ALU
11 = HPDF dither applied in ALU
Note: DITHER[1:0] applies only to the dither mode in the ALU.
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REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
[3:2] DIFF[1:0] 00 00 = Stereo
10 = Stereo reverse (left and right channels swapped)
01 = Mono left – differential outputs
VOUTLP is left channel.
VOUTLN is left channel inverted.
VOUTRP is left channel inverted.
VOUTRN is left channel.
11 = Mono right – differential outputs.
VOUTLP is right channel inverted.
VOUTLN is right channel.
VOUTRP is right channel.
VOUTRN is right channel inverted.
4 DOUT 0 Daisychaining Mode. Audio data output control:
0 = No audio data daisychaining
1 = Audio data output on pin 23
5 SDOUT 0 Daisychaining Mode. Control data output control:
0 = No control data daisychaining
1 = Control data output on pin 25
6 DSD_GAIN 0 DSD Plus gain control:
0 = Low gain, 1.4Vrms differential output level
1 = High gain, 2.0Vrms differential output level
Table 61 R8 Mode Control Register 2
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R9
Software reset
09h
[7:0] RESET 00000000
Software reset. Writing to the register resets the entire chip, including
the register map.
Table 62 R9 Software Reset Control Register
REGISTER
ADDRESS
BITS NAME DEFAULT DESCRIPTION
R32
Additional
Control 1
20h
0 DSD_NO_
NOTCH
0 DSD Direct 8fs Notch Filter
0: Enable 8fs notch filter
1: Disable 8fs notch filter
1 DSD_LEVEL 1
DSD Direct Filter Gain
0: High Gain
1: Low Gain
Table 63 R32 Additional Control 1
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DIGITAL FILTER CHARACTERISTICS
PCM MODE FILTER CHARACTERISTICS
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Low Rate (32/44.1/48kHz) PCM Filter Response 1
Passband 0.000057dB
0.454fs
Passband Ripple 0.000057 dB
Stopband
0.546fs
Stopband Attenuation -111.8
dB
Attenuation at fs/2 -6.02 dB
Group Delay 43 fs
Low Rate (32/44.1/48kHz) PCM Filter Response 2
Passband 0.000036 dB
0.408fs
Passband Ripple 0.000036 dB
Stopband
0.522fs
Stopband Attenuation -111.1
dB
Attenuation at fs/2 Fs/2 -28.07 dB
Group Delay 8 fs
Low Rate (32/44.1/48kHz) PCM Filter Response 3
Passband 0.000058 dB
0.454fs
Passband Ripple 0.000058 dB
Stopband
0.546fs
Stopband Attenuation -110.3
dB
Attenuation at fs/2 Fs/2 -6.43 dB
Group Delay 7 fs
Low Rate (32/44.1/48kHz) PCM Filter Response 4
Passband 0.000066 dB
0.417fs
Passband Ripple 0.000066 dB
Stopband
0.500fs
Stopband Attenuation -110.4
dB
Attenuation at fs/2 Fs/2 -116.19 dB
Group Delay 47 fs
Low Rate (32/44.1/48kHz) PCM Filter Response 5
Passband 0.000041 dB
0.417fs
Passband Ripple 0.000041 dB
Stopband
0.500fs
Stopband Attenuation -111.8
dB
Attenuation at fs/2 Fs/2 -112.45 dB
Group Delay 8 fs
Table 64 Low Rate PCM Filter Characteristics
Production Data WM8741
w PD, Rev 4.3, February 2013
51
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Medium Rate (88.2/96kHz) PCM Filter Response 1
Passband 0.000021 dB
0.208fs
Passband Ripple 0.000021 dB
Stopband
0.500fs
Stopband Attenuation -120.3
dB
Attenuation at fs/2 Fs/2 -120.41 dB
Group Delay 17 fs
Medium Rate (88.2/96kHz) PCM Filter Response 2
Passband 0.000014 dB
0.208fs
Passband Ripple 0.000014 dB
Stopband
0.500fs
Stopband Attenuation -120.8
dB
Attenuation at fs/2 Fs/2 -127.96 dB
Group Delay 9 fs
Medium Rate (88.2/96kHz) PCM Filter Response 3
Passband 0.000048 dB
0.417fs
Passband Ripple 0.000048 dB
Stopband
0.500fs
Stopband Attenuation -115.5
dB
Attenuation at fs/2 Fs/2 -116.89 dB
Group Delay 48 fs
Medium Rate (88.2/96kHz) PCM Filter Response 4
Passband 0.000021 dB
0.208fs
Passband Ripple 0.000021 dB
Stopband
0.458fs
Stopband Attenuation -120.0
dB
Attenuation at fs/2 Fs/2 -126.82 dB
Group Delay 9 fs
Medium Rate (88.2/96kHz) PCM Filter Response 5
Passband 0.000023 dB
0.208fs
Passband Ripple 0.000023 dB
Stopband
0.458fs
Stopband Attenuation -122.5
dB
Attenuation at fs/2 Fs/2 -130.52 dB
Group Delay 8 fs
Table 65 Medium Rate PCM Filter Characteristics
WM8741 Production Data
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52
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
High Rate (176.4/192kHz) PCM Filter Response 1
Passband 0.000010 dB
0.104fs
Passband Ripple 0.000010 dB
Stopband
0.500fs
Stopband Attenuation -120.0
dB
Attenuation at fs/2 Fs/2 -127.5 dB
Group Delay 10 fs
High Rate (176.4/192kHz) PCM Filter Response 2
Passband 0.000031 dB
0.104fs
Passband Ripple 0.000031 dB
Stopband
0.500fs
Stopband Attenuation -120.0
dB
Attenuation at fs/2 Fs/2 -124.93 dB
Group Delay 4 fs
High Rate (176.4/192kHz) PCM Filter Response 3
Passband 0.000873 dB
0.400fs
Passband Ripple 0.000873 dB
Stopband
0.500fs
Stopband Attenuation -110.1
dB
Attenuation at fs/2 Fs/2 -112.67 dB
Group Delay 31 fs
High Rate (176.4/192kHz) PCM Filter Response 4
Passband 0.000015 dB
0.104fs
Passband Ripple 0.000015 dB
Stopband
0.400fs
Stopband Attenuation -120.0
dB
Attenuation at fs/2 Fs/2 -120.58 dB
Group Delay 6 fs
High Rate (176.4/192kHz) PCM Filter Response 5
Passband 0.000001 dB
0.104fs
Passband Ripple 0.000001 dB
Stopband
0.400fs
Stopband Attenuation -122.8
dB
Attenuation at fs/2 Fs/2 -128.58 dB
Group Delay 18 fs
Table 66 High Rate PCM Filter Characteristics
8FS MODE FILTER CHARACTERISTICS
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
8FS Mode Filter
Passband 0.000021 dB
0.455 fs
Passband Ripple 0.000021 dB
Filter Cut-off -3dB point 121.13 kHz
Group Delay 5 fs
Table 67 8FS Mode Filter Characteristics
Production Data WM8741
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53
DSD PLUS MODE FILTER CHARACTERISTICS
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
DSD Plus Filter Response 1
Passband 0.020423 dB
22.48 kHz
Passband Ripple 0.020423 dB
Stopband
127.69
kHz
Stopband Attenuation -38.51
dB
Filter Cut-off -3dB point 58.91 kHz
Group Delay 71 fs
DSD Plus Filter Response 2
Passband 0.011308dB
23.04 kHz
Passband Ripple 0.011308 dB
Stopband
120.41
kHz
Stopband Attenuation -44.52
dB
Filter Cut-off -3dB point 49.83 kHz
Group Delay 127 fs
DSD Plus Filter Response 3
Passband 0.019762 dB
27.35 kHz
Passband Ripple 0.019762 dB
Stopband
70.14
kHz
Stopband Attenuation -26.28
dB
Filter Cut-off -3dB point 49.74 kHz
Group Delay 46 Fs
DSD Plus Filter Response 4
Passband 0.004140 dB
20.24 kHz
Passband Ripple 0.004140 dB
Stopband
70.03
kHz
Stopband Attenuation -48.05
dB
Filter Cut-off -3dB point 49.78 kHz
Group Delay 127 fs
Table 68 DSD Plus Filter Characteristics
WM8741 Production Data
w PD, Rev 4.3, February 2013
54
PCM MODE FILTER RESPONSES
-200
-150
-100
-50
0
0 0.5 1 1.5 2 2.5 3 3.5 4
Frequency (fs)
Response (dB)
Figure 28 Low Rate PCM Filter 1 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 29 Low Rate PCM Filter 1 Ripple
-200
-150
-100
-50
0
00.511.522.533.54
Frequency (fs)
Response (dB)
Figure 30 Low Rate PCM Filter 2 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 31 Low Rate PCM Filter 2 Ripple
-200
-150
-100
-50
0
00.511.522.533.54
Frequency (fs)
Response (dB)
Figure 32 Low Rate PCM Filter 3 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 33 Low Rate PCM Filter 3 Ripple
Production Data WM8741
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-200
-150
-100
-50
0
00.511.522.533.54
Frequency (fs)
Response (dB)
Figure 34 Low Rate PCM Filter 4 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 35 Low Rate PCM Filter 4 Ripple
-200
-150
-100
-50
0
00.511.522.533.54
Frequency (fs)
Response (dB)
Figure 36 Low Rate PCM Filter 5 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 37 Low Rate PCM Filter 5 Ripple
-200
-150
-100
-50
0
0 0.5 1 1.5 2
Frequency (fs)
Response (dB)
Figure 38 Medium Rate PCM Filter 1 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.05 0.1 0.15 0.2 0.25
Frequency (fs)
Response (dB x 10-3)
Figure 39 Medium Rate PCM Filter 1 Ripple
WM8741 Production Data
w PD, Rev 4.3, February 2013
56
-200
-150
-100
-50
0
0 0.5 1 1.5 2
Frequency (fs)
Response (dB)
Figure 40 Medium Rate PCM Filter 2 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.05 0.1 0.15 0.2 0.25
Frequency (fs)
Response (dB x 10-3)
Figure 41 Medium Rate PCM Filter 2 Ripple
-200
-150
-100
-50
0
0 0.5 1 1.5 2
Frequency (fs)
Response (dB)
Figure 42 Medium Rate PCM Filter 3 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.05 0.1 0.15 0.2 0.25
Frequency (fs)
Response (dB x 10-3)
Figure 43 Medium Rate PCM Filter 3 Ripple
-200
-150
-100
-50
0
0 0.5 1 1.5 2
Frequency (fs)
Response (dB)
Figure 44 Medium Rate PCM Filter 4 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.05 0.1 0.15 0.2 0.25
Frequency (fs)
Response (dB x 10-3)
Figure 45 Medium Rate PCM Filter 4 Ripple
Production Data WM8741
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57
-200
-150
-100
-50
0
0 0.5 1 1.5 2
Frequency (fs)
Response (dB)
Figure 46 Medium Rate PCM Filter 5 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.05 0.1 0.15 0.2 0.25
Frequency (fs)
Response (dB x 10-3)
Figure 47 Medium Rate PCM Filter 5 Ripple
-200
-150
-100
-50
0
0 0.2 0.4 0.6 0.8 1
Frequency (fs)
Response (dB)
Figure 48 High Rate PCM Filter 1 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.025 0.05 0.075 0.1 0.125 0.15
Frequency (fs)
Response (dB x 10-3)
Figure 49 High Rate PCM Filter 1 Ripple
-200
-150
-100
-50
0
0 0.2 0.4 0.6 0.8 1
Frequency (fs)
Response (dB)
Figure 50 High Rate PCM Filter 2 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.025 0.05 0.075 0.1 0.125 0.15
Frequency (fs)
Response (dB x 10-3)
Figure 51 High Rate PCM Filter 2 Ripple
WM8741 Production Data
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58
-200
-150
-100
-50
0
0 0.2 0.4 0.6 0.8 1
Frequency (fs)
Response (dB)
Figure 52 High Rate PCM Filter 3 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.025 0.05 0.075 0.1 0.125 0.15
Frequency (fs)
Response (dB x 10-3)
Figure 53 High Rate PCM Filter 3 Ripple
-200
-150
-100
-50
0
0 0.2 0.4 0.6 0.8 1
Frequency (fs)
Response (dB)
Figure 54 High Rate PCM Filter 4 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.025 0.05 0.075 0.1 0.125 0.15
Frequency (fs)
Response (dB x 10-3)
Figure 55 High Rate PCM Filter 4 Ripple
-200
-150
-100
-50
0
0 0.2 0.4 0.6 0.8 1
Frequency (fs)
Response (dB)
Figure 56 High Rate PCM Filter 5 Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.025 0.05 0.075 0.1 0.125 0.15
Frequency (fs)
Response (dB x 10-3)
Figure 57 High Rate PCM Filter 5 Ripple
Production Data WM8741
w PD, Rev 4.3, February 2013
59
8FS MODE FILTER RESPONSES
-200
-150
-100
-50
0
00.511.522.533.54
Frequency (fs)
Response (dB)
Figure 58 8FS Mode Filter Frequency Response
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.1 0.2 0.3 0.4 0.5
Frequency (fs)
Response (dB x 10-3)
Figure 59 8FS Mode Filter Ripple
DSD PLUS MODE FILTER RESPONSES
-100
-80
-60
-40
-20
0
0 50 100 150 200
Frequency (kHz)
Response (dB)
Figure 60 DSD Plus Mode Filter 1 Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10-3)
Figure 61 DSD Plus Mode Filter 1 Ripple
-100
-80
-60
-40
-20
0
0 50 100 150 200
Frequency (kHz)
Response (dB)
Figure 62 DSD Plus Mode Filter 2 Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10-3)
Figure 63 DSD Plus Mode Filter 2 Ripple
WM8741 Production Data
w PD, Rev 4.3, February 2013
60
-100
-80
-60
-40
-20
0
0 50 100 150 200
Frequency (kHz)
Response (dB)
Figure 64 DSD Plus Mode Filter 3 Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10-3)
Figure 65 DSD Plus Mode Filter 3 Ripple
-100
-80
-60
-40
-20
0
0 50 100 150 200
Frequency (kHz)
Response (dB)
Figure 66 DSD Plus Mode Filter 4 Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10-3)
Figure 67 DSD Plus Mode Filter 4 Ripple
DSD DIRECT MODE FILTER RESPONSES
-100
-80
-60
-40
-20
0
0 50 100 150 200 250 300 350 400
Frequency (kHz)
Response (dB)
Figure 68 DSD Direct Mode Standard Low Gain Filter
Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10
-3
)
Figure 69 DSD Direct Mode Standard Low Gain Filter Ripple
(Normalised)
Production Data WM8741
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61
-100
-80
-60
-40
-20
0
0 50 100 150 200 250 300 350 400
Frequency (kHz)
Response (dB)
Figure 70 DSD Direct Mode Standard High Gain Filter
Frequency Response
-25
-20
-15
-10
-5
0
5
10
15
20
25
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10
-3
)
Figure 71 DSD Direct Mode Standard High Gain Filter Ripple
(Normalised)
-100
-80
-60
-40
-20
0
0 50 100 150 200 250 300 350 400
Frequency (kHz)
Response (dB)
Figure 72 DSD Direct Mode 8fs Notch Low Gain Filter
Frequency Response
-15
-10
-5
0
5
10
15
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10
-3
)
Figure 73 DSD Direct Mode 8fs Notch Low Gain Filter Ripple
(Normalised)
-100
-80
-60
-40
-20
0
0 50 100 150 200 250 300 350 400
Frequency (kHz)
Response (dB)
Figure 74 DSD Direct Mode 8fs Notch High Gain Filter
Frequency Response
-20
-15
-10
-5
0
5
10
15
20
0 5 10 15 20 25
Frequency (kHz)
Response (dB x 10
-3
)
Figure 75 DSD Direct Mode 8fs Notch High Gain Filter Ripple
(Normalised)
WM8741 Production Data
w PD, Rev 4.3, February 2013
62
DEEMPHASIS FILTER RESPONSES
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 76 De-emphasis Frequency Response (32kHz)
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 77 De-emphasis Error (32kHz)
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 78 De-emphasis Frequency Response (44.1kHz)
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 79 De-emphasis Error (44.1kHz)
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 80 De-emphasis Frequency Response (48kHz)
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0 5000 10000 15000 20000
Frequency (Hz)
Response (dB)
Figure 81 De-emphasis Error (48kHz)
Production Data WM8741
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63
APPLICATIONS INFORMATION
Figure 82 External Components
Figure 83 External Filter Components
WM8741 Production Data
w PD, Rev 4.3, February 2013
64
PACKAGE DIMENSIONS
NOTES:
A. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS.
B. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
C. BODY DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSION, NOT TO EXCEED 0.20MM.
D. MEETS JEDEC.95 MO-150, VARIATION = AH. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS.
DM007.EDS: 28 PIN SSOP (10.2 x 5.3 x 1.75 mm)
Symbols
Dimensions
(mm)
MIN NOM MAX
A----- ----- 2.0
A10.05 ----- 0.25
A21.65 1.75 1.85
b0.22 0.30 0.38
c0.09 ----- 0.25
D9.90 10.20 10.50
e
E7.40 7.80 8.20
5.00 5.30 5.60
L0.55 0.75 0.95
AA2 A1
14
1
15
28
E1 E
cL
GAUGE
PLANE
0.25
e
b
D
SEATING PLANE
-C-
0.10 C
REF: JEDEC.95, MO-150
E1
L11.25 REF
0.65 BSC
L1
0o4o8o
Production Data WM8741
w PD, Rev 4.3, February 2013
65
IMPORTANT NOTICE
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delivery and payment supplied at the time of order acknowledgement.
Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the
right to make changes to its products and specifications or to discontinue any product or service without notice. Customers
should therefore obtain the latest version of relevant information from Wolfson to verify that the information is current.
Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty.
Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation.
In order to minimise risks associated with customer applications, the customer must use adequate design and operating
safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer
product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for
such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product.
Wolfson’s products are not intended for use in life support systems, appliances, nuclear systems or systems where
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ADDRESS:
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Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: sales@wolfsonmicro.com
WM8741 Production Data
w PD, Rev 4.3, February 2013
66
REVISION HISTORY
DATE REV DESCRIPTION OF CHANGES CHANGED BY
11/02/13 4.3
Digital supply operation changed from 3.0V to 3.6V to 3.15 to 3.6V JMacD
11/02/13 4.3
Operating temp changed from -40oC to +85oC to 0oC to +70oC JMacD
Mouser Electronics
Authorized Distributor
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