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DESCRIPTION
WM8746 is a high performance 6-channel DAC designed
for audio applications such as DVD, home theatre systems,
and digital TV. The WM8746 supports data input word
lengths from 16 to 32-bits and sampling rates up to 192kHz.
The WM8746 can convert up to 6 channels at sample rates
from 8 to 192kHz. Additionally WM8746 supports 2
channels at 192kHz and 4 channels at 96kHz
simultaneously.
The WM8746 consists of a serial interface port, digital
interpolation filters, multi-bit sigma delta modulators and 6
DACs in a small 28-pin SSOP package. The WM8746 also
includes a digitally controllable mute and attenuator function
on each channel.
The WM8746 supports a variety of connection schemes for
audio DAC control. The serial control interface 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
WM8736, (apart from RSTB pin which is typically unused).
The WM8746 is an ideal device to interface to AC-3,
DTS, and MPEG audio decoders for surround sound
applications, or for use in “universal” high definition audio
players supporting DVD-A formats.
WM8746
24-bit, 192kHz 6-Channel DAC with Volume Control
FEATURES
•
•
6-Channel DAC
Audio Performance
−
106dB SNR (‘A’ weighted @ 48kHz) DAC
−
-95dB THD
DAC Sampling Frequency: 8kHz – 192kHz
3-Wire Serial Control Interface
Programmable Audio Data Interface Modes
−
•
•
•
•
•
I
2
S, Left, Right Justified or 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-Pin SSOP Package
Exceeds Dolby Class A Performance Requirements
Pin Compatible with WM8736
•
•
•
APPLICATIONS
•
•
•
DVD and DVD ‘Universal’ Players
Home theatre systems
Digital broadcast receivers
BLOCK DIAGRAM
SCKI
ML/I2S
MC/IWL
MD/DM
MODE
MUTE
WM8746
CONTROL
INTERFACE
ATC
DEEMPH
BCP
PDWN
PL[3:0]
IWL[1:0]
MUTE
UPDATE
LxA[23:0]
LRP
RxA[23:0]
FMT[1:0]
PDWN
PDWN
PDWN
L0A[7:0]
Digital
Filter
Sigma
Delta
Modulator
Stereo
DAC
OUT0L
GR0
OUT0R
BCKIN
LRCIN
LRCIN2
R0A[7:0]
L1A[7:0]
AUDIO
INTERFACE
DAC
CHANNEL
CONTROL
R1A[7:0]
DIN0
DIN1
DIN2
L2A[7:0]
Digital
Filter
Sigma
Delta
Modulator
Stereo
DAC
OUT1L
GR1
OUT1R
Digital
Filter
Sigma
Delta
Modulator
Stereo
DAC
OUT2L
GR2
OUT2R
R2A[7:0]
DVDD
DGND
AGND1
AGND2
AVDD1
AVDD2
CAP
WOLFSON MICROELECTRONICS plc
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Production Data, March 2006, Rev 4.0
Copyright
2006
Wolfson Microelectronics plc
WM8746
Production Data
TABLE OF CONTENTS
DESCRIPTION .......................................................................................................1
FEATURES.............................................................................................................1
APPLICATIONS .....................................................................................................1
BLOCK DIAGRAM .................................................................................................1
TABLE OF CONTENTS .........................................................................................2
PIN CONFIGURATION...........................................................................................3
ORDERING INFORMATION ..................................................................................3
PIN DESCRIPTION ................................................................................................4
ABSOLUTE MAXIMUM RATINGS.........................................................................5
DC ELECTRICAL CHARACTERISTICS ........................................................................ 6
AC ELECTRICAL CHARACTERISTICS ........................................................................ 6
TERMINOLOGY ............................................................................................................ 7
MASTER CLOCK TIMING ............................................................................................. 8
DIGITAL AUDIO INTERFACE TIMING.......................................................................... 8
DIGITAL CONTROL INTERFACE ................................................................................. 9
DEVICE DESCRIPTION.......................................................................................10
INTRODUCTION ......................................................................................................... 10
AUDIO DATA SAMPLING RATES............................................................................... 10
DIGITAL AUDIO INTERFACE ..................................................................................... 11
MODES OF OPERATION ........................................................................................... 14
SOFTWARE CONTROL MODES................................................................................ 15
HARDWARE CONTROL MODES ............................................................................... 21
SOFTWARE CONTROL INTERFACE......................................................................... 22
REGISTER MAP...................................................................................................23
DAC FILTER RESPONSES .................................................................................26
DIGITAL DE-EMPHASIS CHARACTERISTICS ...................................................27
RECOMMENDED EXTERNAL COMPONENTS ..................................................28
RECOMMENDED EXTERNAL COMPONENTS VALUES ........................................... 28
DECOUPLING APPLICATIONS INFORMATION ................................................29
SUPPLY PINS DESCRIPTION.................................................................................... 29
DC ELECTRICAL CHARACTERISTICS ...................................................................... 29
DECOUPLING EXAMPLES......................................................................................... 29
RECOMMENDED ANALOGUE LOW-PASS FILTER (OPTIONAL) ....................30
PACKAGE DIMENSIONS ....................................................................................31
IMPORTANT NOTICE ..........................................................................................32
ADDRESS: .................................................................................................................. 32
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WM8746
PIN CONFIGURATION
Production Data
ORDERING INFORMATION
DEVICE
WM8746SEDS
WM8746SEDS/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
(Pb-free, tape and reel)
MSL1
260°C
MOISTURE
SENSITIVITY LEVEL
MSL1
PEAK SOLDERING
TEMPERATURE
260°C
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March 2006, PD Rev 4.0
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WM8746
PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
NAME
DVDD
SCKI
BCKIN
LRCIN
DIN0
DIN1
DIN2
MODE
TYPE
Supply
Digital input
Digital input
Digital input
Digital input
Digital input
Digital input
Digital input
Internal pull-up
Digital bidirectional
Digital Positive Supply.
System Clock Input
Audio Data Bit Clock Input.
DAC Sample Rate Clock Input
Channel 0 Serial Audio Data Input.
Channel 1 Serial Audio Data Input.
Channel 2 Serial Audio Data Input.
Control Method Selection Pin.
Low = Software Mode
High = Hardware Control Mode
Mute Control Pin in PCM Mode.
Input
Low: Not Mute
High: Mute
Z: Automute
10
11
12
LRCIN2
DGND
ML/I2S
Digital input
Internal pull-down
Supply
Digital input
Internal pull-up
Digital input
Internal pull-up
Digital input
Supply
Analogue output
Analogue output
Analogue input
Analogue output
Supply
Analogue output
Analogue input
Analogue output
Supply
Analogue output
Analogue input
Analogue output
Supply
DESCRIPTION
Production Data
9
MUTE
Output (Automute Enabled)
Low: Mute Off
High: Mute On (Zero Flag)
2
nd
LRCIN for use in mixed 192kHz/96kHz operation (bit 2SPD = ‘hi’)
Digital GND
Software mode: 3-Wire Serial Control Latch
Hardware Mode: Input Format Selection:
Software Mode: 3-Wire Serial Control Clock Input
Hardware mode: Input Word Length Selection:
Software mode: 3-Wire Serial Control Data Input
Hardware mode: De-emphasis selection
Analogue Positive DAC Reference
Analogue Internal Mid-Rail Reference De-Coupling Point
Left Channel 2 Output.
Channel 2 Negative Reference.
Right Channel 2 Output.
Analogue GND
Left Channel 1 Output.
Channel 1 Negative Reference.
Right Channel 1 Output.
Analogue GND
Left Channel 0 Output.
Channel 0 Negative Reference.
Right Channel 0 Output.
Analogue VDD
13
MC/IWL
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Note:
1.
MD/DM
AVDD2
CAP
OUT2L
GR2
OUT2R
AGND1
OUT1L
GR1
OUT1R
AGND2
OUT0L
GR0
OUT0R
AVDD1
Digital input pins have Schmitt trigger input buffers
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WM8746
ABSOLUTE MAXIMUM RATINGS
Production Data
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
-25°C
-65°C
MIN
-0.3V
-0.3V
DGND -0.3V
AGND -0.3V
MAX
+7V
+7V
DVDD +0.3V
AVDD +0.3V
37MHz
+85°C
+150°C
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March 2006, PD Rev 4.0
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