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DESCRIPTION
The WM8706 is a high performance stereo DAC designed
for audio applications such as DVD, home theatre systems,
and digital TV. The WM8706 supports data input word
lengths from 16 to 32-bits and sampling rates up to 192kHz.
The WM8706 can implement 2 channels at 192kHz for high-
end DVD-Audio. The WM8706 consists of a serial interface
port, digital interpolation filters, multi-bit sigma delta
modulators and stereo DAC in a small 28-lead SSOP
package. The WM8706 also includes a digitally controllable
mute and attenuate function on each channel.
The WM8706 supports a variety of connection schemes for
audio DAC control. The MPU serial port provides access to
a wide range of features including on-chip mute, attenuation
and phase reversal. A hardware controllable interface is
also available. It is pin-compatible with the WM8716
provided the oscillator circuit on WM8716 is not required in
the application.
The WM8706 is an ideal device to interface to AC-3,
DTS, and MPEG audio decoders for surround sound
applications, or for use in DVD players supporting DVD-A.
WM8706
24-bit, 192kHz Stereo DAC with Volume Control
FEATURES
•
•
Stereo DAC
Audio Performance
-
•
•
•
106dB SNR (‘A’ weighted @ 48kHz) DAC
-
-97dB THD
DAC Sampling Frequency: 8kHz – 192kHz
3-Wire Serial Control Interface or Hardware Control
Programmable Audio Data Interface Modes
-
I
2
S, Left, Right Justified, DSP
-
16/20/24/32 bit Word Lengths
Independent Digital Volume Control on Each Channel with
127.5dB Range in 0.5dB Steps
3.0V – 5.5V Supply Operation
28-Lead SSOP Package
Exceeds Dolby Class A Performance Requirements
•
•
•
•
APPLICATIONS
•
•
•
•
DVD-Audio and DVD ‘Universal’ Players
Home theatre systems
Digital TV
Digital broadcast receivers
BLOCK DIAGRAM
MODE
MLIIS
MCDM1 MDDM0 MUTEB CSBIWO
ZERO
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CONTROL INTERFACE
WM8706
BCKIN
LRCIN
DIN
SERIAL
INTERFACE
MUTE/
ATTEN
DIGITAL FILTERS
MUTE/
ATTEN
SIGMA
DELTA
MODULATOR
RIGHT
DAC
LOW
PASS
FILTER
VOUTR
SIGMA
DELTA
MODULATOR
LEFT
DAC
LOW
PASS
FILTER
VOUTL
VMID
XTI
AVDD DVDD
VREFP VREFN AGND
DGND
WOLFSON MICROELECTRONICS plc
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Production Data, July 2005, Rev 4.1
Copyright
2005
Wolfson Microelectronics plc
WM8706
Production Data
TABLE OF CONTENTS
DESCRIPTION ............................................................................................................1
FEATURES..................................................................................................................1
APPLICATIONS ..........................................................................................................1
BLOCK DIAGRAM ......................................................................................................1
PIN CONFIGURATION................................................................................................3
ORDERING INFORMATION .......................................................................................3
PIN DESCRIPTION .....................................................................................................4
ABSOLUTE MAXIMUM RATINGS..............................................................................5
DC ELECTRICAL CHARACTERISTICS .....................................................................6
ELECTRICAL CHARACTERISTICS ...........................................................................6
TERMINOLOGY ................................................................................................................. 7
MASTER CLOCK TIMING .................................................................................................. 8
DIGITAL AUDIO INTERFACE ............................................................................................ 8
MPU INTERFACE TIMING ................................................................................................. 9
DEVICE DESCRIPTION............................................................................................10
INTRODUCTION ...............................................................................................................10
CLOCKING SCHEMES .....................................................................................................10
DIGITAL AUDIO INTERFACE ...........................................................................................10
AUDIO DATA SAMPLING RATES.....................................................................................13
HARDWARE CONTROL MODES .....................................................................................13
SOFTWARE CONTROL INTERFACE...............................................................................15
REGISTER MAP ...............................................................................................................16
ATTENUATION CONTROL...............................................................................................18
DIGITAL FILTER CHARACTERISTICS ....................................................................21
DAC FILTER RESPONSES...............................................................................................21
DIGITAL DE-EMPHASIS CHARACTERISTICS ........................................................22
RECOMMENDED EXTERNAL COMPONENTS .......................................................23
RECOMMENDED EXTERNAL COMPONENT VALUES ...................................................23
RECOMMENDED ANALOGUE LOW PASS FILTER (OPTIONAL) .........................24
PACKAGE DIMENSIONS .........................................................................................25
IMPORTANT NOTICE ...............................................................................................26
ADDRESS: ........................................................................................................................26
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WM8706
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PIN CONFIGURATION
LRCIN
DIN
BCKIN
NC
XTI
NC
DGND
DVDD
NC
NC
NC
NC
VOUTR
AGND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
MLIIS
MCDM1
MDDM0
MUTEB
MODE
CSBIWO
NC
ZERO
VREFP
VREFN
VMID
NC
VOUTL
AVDD
ORDERING INFORMATION
DEVICE
WM8706SEDS
TEMPERATURE
RANGE
-25 to +85
o
C
PACKAGE
MOISTURE
SENSITIVITY LEVEL
MSL 1
PEAK SOLDERING
TEMPERATURE
260
o
C
28-lead SSOP
(lead free)
28-lead SSOP
(lead free, tape and
reel)
WM8706SEDS/R
-25 to +85
o
C
MSL 1
260
o
C
Note:
Reel quantity = 2,000
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PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
CSBIWO
MODE
MUTEB
MDDM0
MCDM1
MLIIS
VMID
VREFN
VREFP
ZERO
VOUTR
AGND
AVDD
VOUTL
DGND
DVDD
ZERO
NAME
LRCIN
DIN
BCKIN
TYPE
Digital Input
Digital Input
Digital Input
NC
NC
Supply
Supply
NC
NC
NC
NC
Analogue Output
Supply
Supply
Analogue Output
NC
Analogue Output
Supply
Supply
Digital Output
NC
Digital Input
Digital Input
Digital Bi-directional
Digital Bi-directional
Digital Input
Digital Input
Serial Audio Data Input
Audio Data Bit Clock Input.
No internal connection
No Internal Connection
Digital Ground Supply
Digital Positive Supply
No Internal Connection
No Internal Connection
No Internal Connection
No Internal Connection
Right Channel DAC Output
Analogue Ground Supply
Analogue Positive Supply
Left Channel DAC Output
No Internal Connection
Mid Rail Decoupling Point
DAC Negative Reference – normally AGND, must not be below AGND
DAC Positive Reference – normally AVDD, must not be above AVDD
Infinite Zero Detect Flag
No Internal Connection
Software Mode: 3-Wire Serial Control Chip Select
Hardware Mode: Input Word Length, Pull Up
Control Mode Selection (Low = Hardware, High = Software), Pull Down
Mute Control (L = Mute on, H = Mute off, Z = Automute Enabled), Pull
Up
Software Mode: 3-Wire Serial Control Data Input:
Hardware Mode: De-Emphasis
Software Mode: 3-Wire Serial Control Clock Input
Hardware Mode: De-Emphasis, Pull Down
Software Mode 3-Wire Serial Control Load Input
Hardware Mode: Input Data Format Selection, Pull Up
DESCRIPTION
DAC Sample Rate Clock Input
Digital Output (Open Drain) Infinite ZERO Detect Flag (L=IZD detected, H=IZD not detected)
Note:
Digital input pins have Schmitt trigger input buffers.
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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 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 (XTI)
Operating temperature range, T
A
Storage temperature
Note:
Analogue and digital grounds must always be within 0.3V of each other.
-25°C
-65°C
MIN
-0.3V
-0.3V
DGND -0.3V
AGND -0.3V
MAX
+7V
+7V
DVDD +0.3V
AVDD +0.3V
50MHz
+85°C
+150°C
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