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24-bit, 192kHz 8-Channel DAC
DESCRIPTION
The WM8768 is a multi-channel audio DAC ideal for DVD
and surround sound processing applications for home hi-fi,
automotive and other audio visual equipment.
Four stereo 24-bit multi-bit sigma delta DACs are used with
oversampling digital interpolation filters. Digital audio input
word lengths from 16-32 bits and sampling rates from 8kHz
to 192kHz are supported. Each DAC channel has
independent digital volume and mute control.
The audio data interface supports I
2
S, left justified, right
justified and DSP digital audio formats.
The device is controlled either via a 3 wire serial interface or
directly using the hardware interface. These interfaces
provide access to features including channel selection,
volume controls, mutes, de-emphasis and power
management facilities. The device is available in a 28-lead
SSOP.
WM8768
FEATURES
•
•
•
•
•
8-Channel DAC with PCM.
Audio Performance
−
103dB SNR (‘A’ weighted @ 48kHz) DAC
DAC Sampling Frequency: 8kHz – 192kHz
3-Wire SPI Serial or Hardware Control Interface
Programmable Audio Data Interface Modes
−
I
2
S, Left, Right Justified or DSP
−
16/20/24/32 bit Word Lengths
Four Independent stereo DAC outputs with independent
digital volume controls
Master or Slave Audio Data Interface
2.7V to 5.5V Analogue, 2.7V to 3.6V Digital supply
Operation
28 lead SSOP Package
•
•
•
•
APPLICATIONS
•
•
•
DVD Players
Surround Sound AV Processors and Hi-Fi systems
Automotive Audio
BLOCK DIAGRAM
VREFN
VREFP
DVDD
DGND
AGND
VMID
AVDD
VREFN VREFP
MCLK
LRCLK
BCLK
DIN1
DIN2
DIN3
DIN4
DIGITAL AUDIO
INTERFACE
&
DIGITAL FILTERS
STEREO
DAC
LOW
PASS
FILTER
VOUT1L
VOUT1R
VOUT2L
VOUT2R
VOUT3L
VOUT3R
VOUT4L
VOUT4R
STEREO
DAC
LOW
PASS
FILTER
STEREO
DAC
LOW
PASS
FILTER
STEREO
DAC
LOW
PASS
FILTER
CONTROL INTERFACE
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WM8768
WOLFSON MICROELECTRONICS plc
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TESTREF1
MC/IWL
MODE
MUTE
MD/DM
ML/I2S
Production Data, July 2005, Rev 4.2
Copyright
2005
Wolfson Microelectronics plc
WM8768
TABLE OF CONTENTS
Production Data
DESCRIPTION ................................................................................................................1
FEATURES......................................................................................................................1
APPLICATIONS ..............................................................................................................1
BLOCK DIAGRAM ..........................................................................................................1
TABLE OF CONTENTS ..................................................................................................2
PIN CONFIGURATION 28 LEAD SSOP ........................................................................3
ORDERING INFORMATION ...........................................................................................3
PIN DESCRIPTION – 28 PIN SSOP ...............................................................................4
ABSOLUTE MAXIMUM RATINGS..................................................................................5
RECOMMENDED OPERATING CONDITIONS ..............................................................6
MASTER CLOCK TIMING .......................................................................................................8
DIGITAL AUDIO INTERFACE – MASTER MODE ...................................................................8
DIGITAL AUDIO INTERFACE – SLAVE MODE ......................................................................9
MPU INTERFACE TIMING ....................................................................................................11
INTERNAL POWER ON RESET CIRCUIT ...................................................................12
DEVICE DESCRIPTION................................................................................................13
INTRODUCTION ...................................................................................................................13
PCM AUDIO DATA SAMPLING RATES................................................................................13
HARDWARE CONTROL MODES .........................................................................................14
DIGITAL AUDIO INTERFACE ...............................................................................................16
POWERDOWN MODES .......................................................................................................19
SOFTWARE CONTROL INTERFACE OPERATION.............................................................20
CONTROL INTERFACE REGISTERS ..................................................................................20
REGISTER MAP............................................................................................................32
DIGITAL FILTER CHARACTERISTICS ........................................................................33
DAC FILTER RESPONSES ..........................................................................................33
DIGITAL DE-EMPHASIS CHARACTERISTICS.....................................................................34
APPLICATIONS INFORMATION ..................................................................................35
RECOMMENDED EXTERNAL COMPONENTS ....................................................................35
RECOMMENDED EXTERNAL COMPONENTS VALUES .....................................................35
SUGGESTED ANALOGUE LOW PASS POST DAC FILTERS .............................................36
PACKAGE DRAWING...................................................................................................37
IMPORTANT NOTICE ...................................................................................................38
ADDRESS: ............................................................................................................................38
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PD Rev 4.2 July 2005
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Production Data
WM8768
PIN CONFIGURATION 28 LEAD SSOP
ORDERING INFORMATION
DEVICE
WM8768GEDS
WM8768GEDS/R
Note:
Reel quantity = 2,000
TEMPERATURE
RANGE
-25 to +85
o
C
-25 to +85
o
C
PACKAGE
28-lead SSOP
(Pb-free)
28-lead SSOP
(lPb-free, tape and reel)
MOISTURE
SENSITIVITY LEVEL
MSL3
MSL3
PEAK SOLDERING
TEMPERATURE
260°C
260°C
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PD Rev 4.2 July 2005
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WM8768
PIN DESCRIPTION – 28 LEAD SSOP
PIN
1
NAME
MODE
TYPE
Digital input
Control format selection
0 = Software control
1 = Hardware control
DESCRIPTION
Production Data
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
MCLK
BCLK
LRCLK
DVDD
DGND
DIN1
DIN2
DIN3
DIN4
ML/I2S
MC/IWL
MD/DM
MUTE
TESTREF1
VREFN
VREFP
VMID
VOUT4L
VOUT4R
VOUT1L
VOUT1R
VOUT2L
VOUT2R
VOUT3L
VOUT3R
AGND
AVDD
Digital input
Digital input/output
Digital input/output
Supply
Supply
Digital input
Digital input
Digital input
Digital input
Digital input
Digital input
Digital input
Digital input/output
Analogue output
Analogue input
Analogue input
Analogue output
Analogue output
Analogue output
Analogue output
Analogue output
Analogue output
Analogue output
Analogue output
Analogue output
Supply
Supply
Master clock; 128, 192, 256, 384, 512, 768fs or 1152fs (fs = word clock
frequency)
Audio interface bit clock
Audio left/right word clock
Digital positive supply
Digital negative supply
DAC channel 1 data input
DAC channel 2 data input
DAC channel 3 data input
DAC channel 4 data input
Software Mode: Serial interface Latch signal
Hardware Mode: Input Audio Data Format
Software Mode: Serial control interface clock
Hardware Mode: Audio data input word length
Software Mode: Serial interface data
Hardware Mode: De-emphasis selection
DAC Zero Flag output or DAC mute input
Test Pin
DAC negative reference supply
DAC positive reference supply
Midrail divider decoupling pin; 10uF external decoupling
DAC channel 4 left output
DAC channel 4 right output
DAC channel 1 left output
DAC channel 1 right output
DAC channel 2 left output
DAC channel 2 right output
DAC channel 3 left output
DAC channel 3 right output
Analogue negative supply and substrate connection
Analogue positive supply
Note
: Digital input pins have Schmitt trigger input buffers.
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Production Data
WM8768
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 tests its package types according to IPC/JEDEC J-STD-020B for Moisture Sensitivity to determine acceptable storage
conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30°C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in Ordering Information.
CONDITION
Digital supply voltage
Analogue supply voltage
Voltage range digital inputs
Voltage range analogue inputs
Master Clock Frequency
Operating temperature range, T
A
Storage temperature after soldering
Notes:
1.
Analogue and digital grounds must always be within 0.3V of each other for normal operation of the device.
-25°C
-65°C
MIN
-0.3V
-0.3V
DGND -0.3V
AGND -0.3V
MAX
+5V
+7V
DVDD +0.3V
AVDD +0.3V
37MHz
+85°C
+150°C
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PD Rev 4.2 July 2005
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