WM8768_10 WOLFSON [Wolfson Microelectronics plc], WM8768_10 Datasheet

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WM8768_10

Manufacturer Part Number
WM8768_10
Description
24-bit, 192kHz 8-Channel DAC
Manufacturer
WOLFSON [Wolfson Microelectronics plc]
Datasheet
w
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
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
management facilities. The device is available in a 28-lead
SSOP.
BLOCK DIAGRAM
WOLFSON MICROELECTRONICS plc
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controls,
mutes,
de-emphasis
24-bit, 192kHz 8-Channel DAC
at
2
http://www.wolfsonmicro.com/enews
S, left justified, right
and
power
FEATURES
APPLICATIONS
DVD Players
Surround Sound AV Processors and Hi-Fi systems
Automotive Audio
8-Channel DAC with PCM.
Audio Performance
DAC Sampling Frequency: 8kHz – 192kHz
3-Wire SPI Serial or Hardware Control Interface
Programmable Audio Data Interface Modes
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
103dB SNR (‘A’ weighted @ 48kHz) DAC
I
16/20/24/32 bit Word Lengths
2
S, Left, Right Justified or DSP
Copyright ©2010 Wolfson Microelectronics plc
Production Data, July 2010, Rev 4.3
WM8768

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WM8768_10 Summary of contents

Page 1

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 ...

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WM8768 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 LEAD SSOP ............................................................................4 ABSOLUTE MAXIMUM RATINGS ..................................................................................5 RECOMMENDED OPERATING CONDITIONS ..............................................................6 ELECTRICAL CHARACTERISTICS ...............................................................................6 ...

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Production Data PIN CONFIGURATION 28 LEAD SSOP ORDERING INFORMATION TEMPERATURE DEVICE RANGE o WM8768GEDS/V -25 to +85 o WM8768GEDS/RV -25 to +85 Note: Reel quantity = 2,000 w PACKAGE SENSITIVITY LEVEL 28-lead SSOP C (Pb-free) 28-lead SSOP C (lPb-free, tape ...

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WM8768 PIN DESCRIPTION – 28 LEAD SSOP PIN NAME 1 MODE Digital input 2 MCLK Digital input 3 BCLK Digital input/output 4 LRCLK Digital input/output 5 DVDD 6 DGND 7 DIN1 Digital input 8 DIN2 Digital input 9 DIN3 Digital ...

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Production Data 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 ...

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WM8768 RECOMMENDED OPERATING CONDITIONS PARAMETER Digital supply range Analogue reference supply Analogue supply range Ground AGND, VREFN, DGND Difference DGND to AGND Note: Digital supply DVDD must never be more than 0.3V greater than AVDD for normal operation of the ...

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Production Data 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. 2. All performance measurements done with 20kHz low pass filter, and where noted ...

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WM8768 MASTER CLOCK TIMING MCLK Figure 1 DAC Master Clock Timing Requirements Test Conditions AVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN = 0V, DGND = 0V, T otherwise stated. PARAMETER System Clock Timing Information MCLK System clock pulse ...

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Production Data BCLK (Output) LRCLK (Output) DIN1/2/3/4 Figure 3 Digital Audio Data Timing – Master Mode Test Conditions AVDD, VREFP = 5V, DVDD = 3.3V, AGND, VREFN, DGND = 0V, T otherwise stated. PARAMETER SYMBOL Audio Data Input Timing Information ...

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WM8768 BCLK LRCLK DIN1/2/3/4 Figure 5 Digital Audio Data Timing – Slave Mode Test Conditions AVDD = 5V, DVDD = 3.3V, AGND = 0V, DGND = 0V, T stated. PARAMETER SYMBOL Audio Data Input Timing Information BCLK cycle time t ...

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Production Data MPU INTERFACE TIMING ML/I2S MC/IWL MD/DM Figure 6 SPI Compatible Control Interface Input Timing Test Conditions AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, T PARAMETER MC/IWL rising edge to ML/I2S rising edge MC/IWL pulse cycle ...

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WM8768 INTERNAL POWER ON RESET CIRCUIT Figure 7 Internal Power on Reset Circuit Schematic The WM8768 includes an internal Power-On-Reset Circuit, as shown in Figure 7, which is used reset the digital logic into a default state after power up. ...

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Production Data DEVICE DESCRIPTION INTRODUCTION WM8768 is a complete 8-channel DAC including digital interpolation and decimation filters and switched capacitor multi-bit sigma delta DACs with digital volume controls on each channel and output smoothing filters. The device is implemented as ...

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WM8768 SAMPLING RATE (LRCLK) 128fs 32kHz 4.096 44.1kHz 5.6448 48kHz 6.144 96kHz 12.288 192kHz 24.576 Table 6 System Clock Frequencies Versus Sampling Rate HARDWARE CONTROL MODES When the MODE pin is held high, the following hardware modes of operation are ...

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Production Data In hardware mode (MODE pin set high) the MUTE pin becomes a bi-directional pin. Therefore driven low the device will never softmute driven high then all channels will softmute immediately. However if ...

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WM8768 DIGITAL AUDIO INTERFACE MASTER AND SLAVE MODES The audio interface operates in either Slave or Master mode, selectable using the MS control bit. In both Master and Slave modes DIN1/2/3/4 are always inputs to the WM8768. The default is ...

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Production Data AUDIO INTERFACE FORMATS Audio data is applied to the internal DAC filters via the Digital Audio Interface. 5 popular interface formats are supported: • Left Justified mode • Right Justified mode 2 • mode • DSP ...

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WM8768 RIGHT JUSTIFIED MODE In right justified mode, the LSB of DIN1/2/3/4 is sampled by the WM8768 on the rising edge of BCLK preceding a LRCLK transition. LRCLK are high during the left samples and low during the right samples ...

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Production Data DSP MODE B In DSP mode B, the MSB of DAC channel 1 left data is sampled by the WM8768 on the first BCLK rising edge following a LRCLK rising edge. DAC channel 1 right and DAC channels ...

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WM8768 SOFTWARE CONTROL INTERFACE OPERATION The WM8768 is controlled using a 3-wire serial interface in software mode or pin programmable in hardware mode. The control mode is selected by the state of the MODE pin. 3-WIRE (SPI COMPATIBLE) SERIAL CONTROL ...

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Production Data DAC OUTPUT CONTROL The DAC output control word determines how the left and right inputs to the audio Interface are applied to the left and right DACs: REGISTER ADDRESS DAC Control DAC DIGITAL AUDIO INTERFACE CONTROL REGISTER Interface ...

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WM8768 By default, LRCLK and DIN1/2/3/4 are sampled on the rising edge of BCLK and should ideally change on the falling edge. Data sources that change LRCLK and DIN1/2/3/4 on the rising edge of BCLK can be supported by setting ...

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Production Data SOFTMUTE The digital muting function used in Software and Hardware mode applies a softmute with the operating characteristics shown in Figure 19. 1.5 1 0.5 0 -0.5 -1 -1.5 -2 -2.5 0 Figure 19 Soft Mute Operation When ...

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WM8768 SOFTWARE MUTE MODES The WM8768 can be muted in a number of different ways when in software mode (MODE pin pulled low). Refer to Figure 20 which shows a representation of the interaction between functions described below. DMUTE4, DMUTE(2:0) ...

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Production Data DMUTE AND MUTEALL The WM8768 can be directly muted using the DMUTE and DMUTE4 register bits to control which channels are muted. The mute happens as soon as the serial write is performed. REGISTER ADDRESS DAC4 Control {DMUTE4,DMUTE ...

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WM8768 MUTE PIN AS INPUT The WM8768 can be muted externally by driving the MUTE pin high. When the MUTE pin is driven low the device will never automute, although direct mutes can still be applied via the DMUTE or ...

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Production Data AUTOMUTE The WM8768 can automute by counting zero samples on the DIN1/2/3/4 inputs. When 1024 zero samples are counted on one channel, one of four internal zero flags (zflag1/2/3/4 shown in figure 2) is raised. Depending on the ...

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WM8768 INFINITE ZERO DETECT When it is set, the IZD register causes an analogue mute of the DAC channel output amplifier both when there are 1024 zeros on that channel’s DIN pin or when it is manually muted by DMUTE ...

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Production Data POWERDOWN MODE AND DAC DISABLE Setting the PDWN register bit immediately powers down the DACs on the WM8768, overriding the DACD powerdown bits control bits. All trace of the previous input samples is removed, but all control register ...

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WM8768 MASTER MODE SELECT Control bit MS selects between audio interface Master and Slave Modes. In Master mode LRCLK and BCLK are outputs and are generated by the WM8768. In Slave mode LRCLK and BCLK are inputs to WM8768. REGISTER ...

Page 31

Production Data DAC DIGITAL VOLUME CONTROL The DAC volume may also be adjusted in the digital domain using independent digital attenuation control registers REGISTER BIT LABEL ADDRESS 0000000 7:0 LDA1[7:0] Digital Attenuation 8 UPDATE DACL1 0000001 7:0 RDA1[6:0] Digital Attenuation ...

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WM8768 Note: When MCLK is removed, digital volume settings are re-set to default (0dB). When MCLK is re-applied, the user must write the desired volume level to the volume control registers. Table 16 Digital Volume Control Attenuation Levels SOFTWARE REGISTER ...

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Production Data DIGITAL FILTER CHARACTERISTICS PARAMETER DAC Filter Passband Passband ripple Stopband Stopband Attenuation Group Delay Table 17 Digital Filter Characteristics DAC FILTER RESPONSES 0 -20 -40 -60 -80 -100 -120 0 0.5 1 1.5 Frequency (Fs) Figure 21 DAC ...

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WM8768 DIGITAL DE-EMPHASIS CHARACTERISTICS - Frequency (kHz) Figure 25 De-Emphasis Frequency Response (32kHz - Frequency (kHz) Figure 27 De-Emphasis Frequency Response (44.1kHz) ...

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Production Data APPLICATIONS INFORMATION RECOMMENDED EXTERNAL COMPONENTS Figure 31 Recommended External Component Diagram RECOMMENDED EXTERNAL COMPONENTS VALUES COMPONENT SUGGESTED REFERENCE VALUE C1 and C5 10μ 0.1μF C6 0.1μF C7 10μF C8 0.1μF C9 100μF R1 33Ω Table ...

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WM8768 SUGGESTED ANALOGUE LOW PASS POST DAC FILTERS It is recommended that a lowpass filter be applied to the output from each DAC channel for Hi Fi applications. Typically a second order filter is suitable and provides sufficient attenuation of ...

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Production Data PACKAGE DRAWING DS: 28 PIN SSOP (10.2 x 5.3 x 1.75 mm Dimensions Symbols (mm) MIN NOM A ----- A 0. 1.65 1. 0.22 c 0.09 D 9.90 ...

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... Wolfson’s approval, licence, warranty or endorsement thereof. Any third party trade marks contained in this document belong to the respective third party owner. Reproduction of information from Wolfson datasheets is permissible only if reproduction is without alteration and is accompanied by all associated copyright, proprietary and other notices (including this notice) and conditions. Wolfson is not liable for any unauthorised alteration of such information or for any reliance placed thereon ...

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