WM8771 w 24-bit, 192kHz 8-Channel Codec DESCRIPTION FEATURES The WM8771 is a high performance, multi-channel audio codec. The WM8771 is ideal for surround sound processing applications for home hi-fi, automotive and other audio visual equipment. A stereo 24-bit multi-bit sigma delta ADC is used with a three channel input selector. Each channel has analogue domain mute and programmable gain control. Digital audio output word lengths from 16-32 bits and sampling rates from 8kHz to 96kHz are supported. 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 attenuation and mute control. The audio data interface supports I2S, left justified, right justified and DSP digital audio formats. • Audio Performance • • • • • − 108dB SNR (‘A’ weighted @ 48kHz) DAC − 97dB SNR (‘A’ weighted @ 48kHz) ADC DAC Sampling Frequency: 8kHz – 192kHz ADC Sampling Frequecncy: 8kHz – 96kHz 3-Wire SPI or CCB MPU Serial Control Interface Master or Slave Clocking Mode Programmable Audio Data Interface Modes • • • • • The device is controlled via a 3 wire serial interface. The interface provides access to all features including channel selection, volume controls, mutes, de-emphasis and power management facilities. The device is available in a 64-pin TQFP package. − I2S, Left, Right Justified or DSP − 16/20/24/32 bit Word Lengths Four Independent Stereo DAC Audio Outputs Eight stereo ADC inputs with analogue gain adjust from +19dB to –12dB in 1dB steps 2.7V to 5.5V Analogue, 2.7V to 3.6V Digital supply Operation 5V tolerant digital inputs 64-Pin TQFP Package APPLICATIONS • • Surround Sound Processors Automotive Audio AUDIO INTERFACE STEREO ADC AVDD2 VMIDDAC AGND2 DACREFP2 DACREFP1 DOUT ADCLRC BCLK DACLRC DIN1 DIN2 DIN3 DIN4 MCLK ZFLAG1 ZFLAG2 REFADC AVDD1 VMIDADC AGND1 AINVGL DIGITAL FILTERS STEREO DAC LOW PASS FILTERS VOUT1L DIGITAL FILTERS STEREO DAC LOW PASS FILTERS VOUT2L DIGITAL FILTERS STEREO DAC LOW PASS FILTERS VOUT3L DIGITAL FILTERS STEREO DAC LOW PASS FILTERS VOUT4L VOUT1R VOUT2R & DIGITAL FILTERS VOUT3R VOUT4R MUTE CONTROL INTERFACE w MUTE WM8771 CCB is a trademark of SANYO ELECTRIC CO., LTD WOLFSON MICROELECTRONICS LTD w :: www.wolfsonmicro.com GR1 GR2 DI CL CE RESETB DVDD MUTE DGND AINOPL AINOPR REC1L REC1R REC2L REC2R REC3L REC3R INPUT SOURCE SELECTOR AIN1L AIN1R AIN2L AIN2R AIN3L AIN3R AIN4L AIN4R AIN5L AIN5R AIN6L AIN6R AIN7L AIN7R AIN8L AIN8R AINVGR BLOCK DIAGRAM CCB is SANYO’s original bus format and all the bus addresses are controlled by SANYO. Product Preview, December 2001, Rev 2.0 Copyright 2001 Wolfson Microelectronics Ltd. WM8771 Product Preview 64-pin TQFP DVDD -40 to + 85oC ZFLAG1 WM8771IFT/V ZFLAG2 PACKAGE DOUT TEMP. RANGE DIN1 DEVICE DIN2 DIN3 DIN4 DACLRC ADCLRC MCLK BCLK ORDERING INFORMATION CL DI CE RESETB PIN CONFIGURATION AIN1L 1 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 DGND AIN1R 2 47 AGND2 AIN2L 3 46 VOUT4R AIN2R 4 45 VOUT4L AIN3L 5 44 DACREFP2 AIN3R 6 43 VOUT3R AIN4L 7 42 GR2 AIN4R 8 41 VOUT3L AIN5L 9 40 VMIDDAC AIN5R 10 39 VOUT2R AIN6L AIN8R 33 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 w AVDD2 REC3R REC3L VOUT1L REC2R 34 NC 15 REC2L AIN8L NC VOUT1R AVDD1 35 AGND1 14 VMIDADC AIN7R REFADC DACREFP1 RECR 36 RECL VOUT2L 13 AINOPR 12 AIN7L AINVGR GR1 37 AINVGL 38 AINOPL 11 AIN6R PP Rev 2.0 December 2001 2 WM8771 Product Preview PIN DESCRIPTION PIN NAME TYPE 1 AIN1L Analogue Input Channel 1 left input multiplexor virtual ground DESCRIPTION 2 AIN1R Analogue Input Channel 1 right input multiplexor virtual ground 3 AIN2L Analogue Input Channel 2 left input multiplexor virtual ground 4 AIN2R Analogue Input Channel 2 right input multiplexor virtual ground 5 AIN3L Analogue Input Channel 3 left input multiplexor virtual ground 6 AIN3R Analogue Input Channel 3 right input multiplexor virtual ground 7 AIN4L Analogue Input Channel 4 left input multiplexor virtual ground 8 AIN4R Analogue Input Channel 4 right input multiplexor virtual ground 9 AIN5L Analogue Input Channel 5 left input multiplexor virtual ground 10 AIN5R Analogue Input Channel 5 right input multiplexor virtual ground 11 AIN6L Analogue Input Channel 6 left input multiplexor virtual ground 12 AIN6R Analogue Input Channel 6 right input multiplexor virtual ground 13 AIN7L Analogue Input Channel 7 left input multiplexor virtual ground 14 AIN7R Analogue Input Channel 7 right input multiplexor virtual ground 15 AIN8L Analogue Input Channel 8 left input multiplexor virtual ground 16 AIN8R Analogue Input Channel 8 right input multiplexor virtual ground 17 AINOPL Analogue Output 18 AINVGL Analogue Input Left channel multiplexor virtual ground 19 AINVGR Analogue Input Right channel multiplexor virtual ground 20 AINOPR Analogue Output Right channel multiplexor output 21 REC1L Analogue Output Left channel input mux select output 1 22 REC1R Analogue Output Right channel input mux select output 1 23 REFADC Analogue Output ADC reference buffer decoupling pin; 10uF external decoupling 24 VMIDADC Analogue Output ADC midrail divider decoupling pin; 10uF external decoupling 25 AGND1 Supply Analogue negative supply and substrate connection 26 AVDD1 Supply Analogue positive supply 27 NC No Connect Left channel multiplexor output 28 NC No Connect 29 REC2L Analogue Output Left channel input mux select output 2 30 REC2R Analogue Output Right channel input mux select output 2 31 REC3L Analogue Output Left channel input mux select output 3 32 REC3R Analogue Output Right channel input mux select output 3 33 AVDD2 Supply Analogue positive supply 34 VOUT1L Analogue output DAC channel 1 left output 35 VOUT1R Analogue output DAC channel 1 right output 36 DACREFP1 Supply 37 VOUT2L Analogue output 38 GR1 Supply 39 VOUT2R Analogue output DAC channel 2 right output 40 VMIDDAC Analogue output DAC midrail decoupling pin ; 10uF external decoupling 41 VOUT3L Analogue output DAC channel 3 left output 42 GR2 Supply 43 VOUT3R Analogue output 44 DACREFP2 Supply 45 VOUT4L Analogue output DAC channel 4 left output 46 VOUT4R Analogue output DAC channel 4 right output 47 AGND2 Supply Analogue negative supply and substrate connection 48 DGND Supply Digital negative supply 49 DVDD Supply Digital positive supply 50 ZFLAG1 Digital output DAC Zero Flag output 51 ZFLAG2 Digital output DAC Zero Flag output w DAC positive reference supply DAC channel 2 left output DAC ground reference DAC ground reference DAC channel 3 right output DAC positive reference supply PP Rev 2.0 December 2001 3 WM8771 Product Preview PIN NAME TYPE 52 DOUT Digital output ADC data output DESCRIPTION 53 DIN1 Digital Input DAC channel 1 data input 54 DIN2 Digital Input DAC channel 2 data input 55 DIN3 Digital Input DAC channel 3 data input 56 DIN4 Digital Input DAC channel 4 data input 57 DACLRC Digital input/output DAC left/right word clock 58 ADCLRC Digital input/output ADC left/right word clock 59 BCLK Digital input/output ADC and DAC audio interface bit clock 60 MCLK Digital input Master DAC and ADC clock; 256, 384, 512 or 768fs (fs = word clock frequency) 61 SCLK Digital input Serial interface clock (5V tolerant) 62 SDIN Digital input Serial interface data (5V tolerant) 63 LATCH Digital input Serial interface Latch signal (5V tolerant) 64 RESETB Digital input Device reset input (mutes DAC outputs, resets gain stages to 0dB) (5V tolerant) Note: Digital input pins have Schmitt trigger input buffers and are 5V tolerant. w PP Rev 2.0 December 2001 4 WM8771 Product Preview 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. MIN MAX Digital supply voltage -0.3V +3.63V Analogue supply voltage -0.3V +7V CONDITION Voltage range digital inputs (DI, CL, CE & RESETB) DGND -0.3V +7V Voltage range digital inputs (MCLK, DIN[3:0], ADCLRC, DACLRC & BCLK) DGND -0.3V DVDD + 0.3V Voltage range analogue inputs AGND -0.3V AVDD +0.3V Master Clock Frequency 37MHz Operating temperature range, TA -40°C Storage temperature -65°C +85°C +150°C Package body temperature (soldering 10 seconds) +240°C Package body temperature (soldering 2 minutes) +183°C Notes: 1. Analogue and digital grounds must always be within 0.3V of each other. w PP Rev 2.0 December 2001 5 WM8771 Product Preview RECOMMENDED OPERATING CONDITIONS PARAMETER MAX UNIT Digital supply range DVDD 2.7 3.6 V Analogue supply range AVDD 2.7 5.5 Ground SYMBOL TEST CONDITIONS MIN TYP AGND, DGND 0 Difference DGND to AGND -0.3 0 V V +0.3 V Note: digital supply DVDD must never be more than 0.3V greater than AVDD. ELECTRICAL CHARACTERISTICS 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 Digital Logic Levels (TTL Levels) Input LOW level VIL Input HIGH level VIH 0.8 2.0 Output LOW VOL IOL=1mA Output HIGH VOH IOH=1mA V V 0.1 x VDD 0.9 x VDD V V Analogue Reference Levels Reference voltage VVMID Potential divider resistance RVMID AVDD to VMID and VMID to AGND AVDD/2 – 50mV AVDD/2 AVDD/2 + 50mV V 40k 50k 60k Ohms DAC Performance (Load = 10k ohms, 50pF) 0dBFs Full scale output voltage SNR (Note 1,2) A-weighted, @ fs = 48kHz SNR (Note 1,2) A-weighted @ fs = 96kHz Dynamic Range (Note 2) DNR Total Harmonic Distortion (THD) A-weighted, -60dB full scale input 104 104 1kHz, 0dBFs Vrms 108 dB 108 dB 108 dB -97 DAC channel separation Power Supply Rejection Ratio 1.0 x AVDD/5 -90 100 PSRR dB dB 1kHz 100mVpp 50 dB 20Hz to 20kHz 100mVpp 45 dB ADC Performance Input Signal Level (0dB) 1.0 x AVDD/5 SNR (Note 1,2) A-weighted, 0dB gain @ fs = 48kHz SNR (Note 1,2) Dynamic Range (Note 2) Total Harmonic Distortion (THD) ADC Channel Separation w 93 Vrms 97 dB A-weighted, 0dB gain @ fs = 96kHz 94 dB A-weighted, -60dB full scale input 97 dB kHz, 0dBFs -90 -87 dB 1kHz, -3dBFs -95 -90 dB 1kHz Input 90 dB PP Rev 2.0 December 2001 6 WM8771 Product Preview Test Conditions AVDD = 5V, DVDD = 3.3V, AGND = 0V, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated. PARAMETER SYMBOL TEST CONDITIONS Programmable Gain Step Size Programmable Gain Range 1kHz Input Mute Attenuation Power Supply Rejection Ratio MIN TYP MAX UNIT 0.5 1.0 1.5 dB -12 0 +19 dB 1kHz Input, 0dB gain PSRR 97 dB 1kHz 100mVpp 50 dB 20Hz to 20kHz 100mVpp 45 dB AVDD = 5V 100 mA DVDD = 3.3V 20 mA Supply Current Analogue supply current Digital supply current 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 an A-weight filter. Failure to use such a filter will result in higher THD+N 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. 3. VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance). TERMINOLOGY 1. Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full scale output and the output with no signal applied. (No Auto-zero or Automute function is employed in achieving these results). 2. Dynamic range (dB) - DNR is a measure of the difference between the highest and lowest portions of a signal. Normally a THD+N measurement at 60dB below full scale. The measured signal is then corrected by adding the 60dB to it. (e.g. THD+N @ -60dB= -32dB, DR= 92dB). 3. THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal. 4. Stop band attenuation (dB) - Is the degree to which the frequency spectrum is attenuated (outside audio band). 5. Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from the other. Normally measured by sending a full scale signal down one channel and measuring the other. 6. Pass-Band Ripple - Any variation of the frequency response in the pass-band region. w PP Rev 2.0 December 2001 7 WM8771 Product Preview MASTER CLOCK TIMING tMCLKL MCLK tMCLKH tMCLKY Figure 1 Master Clock Timing Requirements Test Conditions AVDD = 5V, DVDD = 3.3V, AGND = 0V, AGND, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated. PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT System Clock Timing Information MCLK System clock pulse width high tMCLKH 11 ns MCLK System clock pulse width low tMCLKL 11 ns MCLK System clock cycle time tMCLKY 28 MCLK Duty cycle 40:60 ns 60:40 Table 1 Master Clock Timing Requirements w PP Rev 2.0 December 2001 8 WM8771 Product Preview DIGITAL AUDIO INTERFACE – MASTER MODE BCLK ADCLRC WM8771 CODEC DACLRC DSP/ ENCODER/ DECODER DOUT DIN1/2/3/4 4 Figure 2 Audio Interface - Master Mode BCLK (Output) tDL ADCLRC/ DACLRC (Outputs) tDDA DOUT DIN1/2/3/4 tDST tDHT Figure 3 Digital Audio Data Timing – Master Mode Test Conditions AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, TA = +25oC, Master Mode, fs = 48kHz, MCLK = 256fs unless otherwise stated. PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT Audio Data Input Timing Information ADCLRC/DACLRC propagation delay from BCLK falling edge tDL 0 10 ns DOUT propagation delay from BCLK falling edge tDDA 0 10 ns DIN1/2/3/4 setup time to BCLCK rising edge tDST 10 ns DIN1/2/3/4 hold time from BCLK rising edge tDHT 10 ns Table 2 Digital Audio Data Timing – Master Mode w PP Rev 2.0 December 2001 9 WM8771 Product Preview DIGITAL AUDIO INTERFACE – SLAVE MODE BCLK ADCLRC WM8771 CODEC DACLRC DSP ENCODER/ DECODER DOUT DIN1/2/3/4 4 Figure 4 Audio Interface – Slave Mode tBCH tBCL BCLK tBCY DACLRC/ ADCLRC tDS tLRH tLRSU DIN1/2/3/4 tDD tDH DOUT Figure 5 Digital Audio Data Timing – Slave Mode Test Conditions AVDD = 5V, DVDD = 3.3V, AGND = 0V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK = 256fs unless otherwise stated. PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT Audio Data Input Timing Information BCLK cycle time tBCY 50 ns BCLK pulse width high tBCH 20 ns BCLK pulse width low tBCL 20 ns DACLRC/ADCLRC set-up time to BCLK rising edge tLRSU 10 ns DACLRC/ADCLRC hold time from BCLK rising edge tLRH 10 ns DIN1/2/3/4 set-up time to BCLK rising edge tDS 10 ns DIN1/2/3/4 hold time from BCLK rising edge tDH 10 ns DOUT propagation delay from BCLK falling edge tDD 0 10 ns Table 3 Digital Audio Data Timing – Slave Mode Note: ADCLRC and DACLRC should be synchronous with MCLK, although the WM8771 interface is tolerant of phase variations or jitter on these signals. w PP Rev 2.0 December 2001 10 WM8771 Product Preview MPU INTERFACE TIMING tRCSU tRCHO RESETB tCSL tCSH CE tSCY tSCH tCSS tSCS tSCL CL DI LSB tDSU tDHO Figure 6 SPI compatible Control Interface Input Timing Test Conditions AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated SYMBOL MIN CE to RESETB hold time PARAMETER tRCSU 20 TYP MAX UNIT ns RESETB to CL setup time tRCHO 20 ns CL rising edge to CE rising edge tSCS 60 ns CL pulse cycle time tSCY 80 ns CL pulse width low tSCL 30 ns CL pulse width high tSCH 30 ns DI to CL set-up time tDSU 20 ns CL to DI hold time tDHO 20 ns CE pulse width low tCSL 20 ns CE pulse width high tCSH 20 ns CE rising to CL rising tCSS 20 ns Table 4 3 wire SPI compatible Control Interface Input Timing Information w PP Rev 2.0 December 2001 11 WM8771 Product Preview tRCES tRCLH RESETB tCP tCS tCH CE tSCY tSCL tSCH CL A7 DI tDSU D15 tDHO Figure 7 3 wire CCB compatible Interface Input Timing Information – CL stopped low tRCES tRCLH RESETB tCH tCP tCS CE tSCY tSCH tSCL CL DI A7 tDSU D15 tDHO Figure 8 3 wire CCB compatible Interface Input Timing Information – CL stopped high Test Conditions AVDD = 5V, DVDD = 3.3V, AGND, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated SYMBOL MIN CE to RESETB setup time PARAMETER tRCES 20 TYP MAX UNIT ns RESETB to CL hold time tRCLH 20 ns DI to CL setup time tDSU 20 ns CL to DI hold time tDHO 20 ns CL to CE setup time tCS 20 ns CE to CL wait time tCP 20 ns CL to CE hold time tCH 20 ns CL pulse width high tSCH 30 ns CL pulse width low tSCL 30 ns CL pulse cycle time tSCY 80 ns Table 5 3 wire CCB compatible Interface Input Timing Information w PP Rev 2.0 December 2001 12 WM8771 Product Preview DEVICE DESCRIPTION INTRODUCTION WM8771 is a complete 8-channel DAC, 2-channel ADC audio codec, including digital interpolation and decimation filters, multi-bit sigma delta stereo ADC, and switched capacitor multi-bit sigma delta DACs with digital volume controls on each channel and output smoothing filters. The device is implemented as four separate stereo DACs and a stereo ADC with flexible input multiplexor, in a single package and controlled by a single interface. The four stereo channels may either be used to implement a 5.1 channel surround system, with additional stereo channel for a stereo mix down channel, or for a complete 7.1 channel surround system. Each stereo DAC has its own data input DIN1/2/3/4. DAC word clock DACLRC is shared between them. The stereo ADC has it’s own data output DOUT, and word clock ADCLRC. BITCLK and MCLK are shared between the ADCs and DACs. The Audio Interface may be configured to operate in either master or slave mode. In Slave mode ADCLRC, DACLRC and BCLK are all inputs. In Master mode ADCLRC, DACLRC and BCLK are all outputs. The input multiplexor to the ADC is configured to allow large signal levels to be input to the ADC, using external resistors to reduce the amplitude of larger signals to within the normal operating range of the ADC. The ADC input PGA also allows input signals to be gained up to +19dB and attenuated down to -12dB. This allows the user maximum flexibility in the use of the ADC. Three individually selectable stereo record outputs are also provided on REC1/2/3. It is intended that the REC1/2/3 outputs are only used to drive high impedance buffers. Each DAC has its own digital volume control. In addition a zero cross detect circuit is provided for each DAC. The digital volume control detects a transition through the zero point before updating the volume. This minimises audible clicks and ‘zipper’ noise as the gain values change. Control of internal functionality of the device is by 3-wire serial control interface. An SPI or CCB type interface may used, selectable by the state of the CE pin on the rising edge of RESETB. The control interface may be asynchronous to the audio data interface as control data will be re-synchronised to the audio processing internally. Operation using system clock of 128fs, 192fs, 256fs, 384fs, 512fs or 768fs is provided. In Slave mode selection between clock rates is automatically controlled. In master mode the master clock to sample rate ratio is set by control bits ADCRATE and DACRATE. ADC and DAC may run at different rates within the constraint of a common master clock for the ADC and DACs. For example with master clock at 24.576MHz, a DAC sample rate of 96kHz (256fs mode) and an ADC sample rate of 48kHz (512fs mode) can be accommodated. Master clock sample rates (fs) from less than 8ks/s up to 192ks/s are allowed, provided the appropriate system clock is input. The audio data interface supports right, left and I2S interface formats along with a highly flexible DSP serial port interface. w PP Rev 2.0 December 2001 13 WM8771 Product Preview AUDIO DATA SAMPLING RATES 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. 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 ADC and DAC. The master clock for WM8771 supports audio sampling rates from 128fs to 768fs, where fs is the audio sampling frequency (DACLRC or ADCLRC) typically 32kHz, 44.1kHz, 48kHz, 96kHz or 192kHz (for DAC operation only). The master clock is used to operate the digital filters and the noise shaping circuits. In Slave mode the WM8771 has a master clock detection circuit that automatically determines the relationship between the system clock frequency and the sampling rate (to within +/- 32 system clocks). If there is a greater than 32 clocks error the interface is disabled and maintains the output level at the last sample. The master clock must be synchronised with ADCLRC/DACLRC, although the WM8771 is tolerant of phase variations or jitter on this clock. SAMPLING RATE (DACLRC/ ADCLRC) System Clock Frequency (MHz) 128fs 192fs 256fs 384fs 512fs 768fs 32kHz 4.096 6.144 8.192 12.288 16.384 24.576 44.1kHz 5.6448 8.467 11.2896 16.9340 22.5792 33.8688 24.576 36.864 48kHz 6.114 9.216 12.288 18.432 96kHz 12.288 18.432 24.576 36.864 192kHz 24.576 36.864 Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Table 6 System Clock Frequencies Versus Sampling Rate In Master mode BCLK, DACLRC and ADCLRC are generated by the WM8771. The frequencies of ADCLRC and DACLRC are set by setting the required ratio of MCLK to DACLRC and ADCLRC using the DACRATE and ADCRATE control bits (Table 7). ADCRATE[2:0]/ DACRATE[2:0] MCLK:ADCLRC/DACLRC RATIO 000 128fs 001 192fs 010 256fs 011 384fs 100 512fs 101 768fs Table 7 Master Mode MCLK:ADCLRC/DACLRC ratio select w PP Rev 2.0 December 2001 14 WM8771 Product Preview SAMPLING RATE (DACLRC/ ADCLRC) System Clock Frequency (MHz) 128fs 192fs 256fs 384fs 512fs 768fs ADCRATE/ DACRATE =000 ADCRATE/ DACRATE =001 ADCRATE/ DACRATE =010 ADCRATE/ DACRATE =011 ADCRATE/ DACRATE =100 ADCRATE/ DACRATE =101 32kHz 4.096 6.144 8.192 12.288 16.384 24.576 44.1kHz 5.6448 8.467 11.2896 16.9340 22.5792 33.8688 48kHz 6.114 9.216 12.288 18.432 24.576 36.864 96kHz 12.288 18.432 24.576 36.864 192kHz 24.576 36.864 Unavailable Unavailable Unavailable Unavailable Unavailable Unavailable Table 8 Master Mode ADC/DACLRC frequency selection BCLK is also generated by the WM8771. The frequency of BCLK depends on the mode of operation. In 128/192fs modes (ADCRATE/DACRATE=000 or 001) BCLK = MCLK/2. In 256/384/512fs modes (ADCRATE/DACRATE=010 or 011 or 100) BCLK = MCLK/4. However if DSP mode is selected as the audio interface mode then BCLK=MCLK. This is to ensure that there are sufficient BCLKs to clock in all eight channels. Note that DSP mode cannot be used in 128fs mode for word lengths greater than 16 bits or in 192fs mode for word lengths greater than 24 bits. ZERO DETECT The WM8770 has a zero detect circuit for each DAC channel which detects when 1024 consecutive zero samples have been input. Two zero flag outputs (ZFLAG1 and ZFLAG2) may be programmed to output the zero detect signals (see Table 9) which may then be used to control external muting circuits. A ‘1’ on ZFLAG1 or ZFLAG2 indicates a zero detect. The zero detect may also be used to automatically enable the PGA mute by setting IZD. The zero flag output may be disabled by setting DZFM to 0000. The zero flag signal for a DAC channel will only be enabled if that channel is enabled as an input to the output summing stage. DZFM[3:0] ZFLAG1 ZFLAG2 0000 Zero flag disabled Zero flag disabled 0001 All channels zero All channels zero 0010 Left channels zero Right channels zero 0011 Channel 1 zero Channels 2-4 zero 0100 Channel 1 zero Channel 2 zero 0101 Channel 1 zero Channel 3 zero 0110 Channel 1 zero Channel 4 zero 0111 Channel 2 zero Channel 3 zero 1000 Channel 2 zero Channel 4 zero 1001 Channel 3 zero Channel 4 zero 1010 Channels 1-3 zero Channel 4 zero 1011 Channel 1 zero Channels 2 & 3 zero 1100 Channel 1 left zero Channel 1 right zero 1101 Channel 2 left zero Channel 2 right zero 1110 Channel 3 left zero Channel 3 right zero 1111 Channel 4 left zero Channel 4 right zero Table 9 Zero Flag Output Select w PP Rev 2.0 December 2001 15 WM8771 Product Preview POWERDOWN MODES The WM8771 has powerdown control bits allowing specific parts of the WM8771 to be powered off when not being used. The 8-channel input source selector and input buffer may be powered down using control bit AINPD. When AINPD is set all inputs to the source selector (AIN1l/R to AIN8L/R) are switched to a buffered VMIDADC. Control bit ADCPD powers off the ADC and also the ADC input PGAs. The four stereo DACs each have a separate powerdown control bit, DACPD[3:0] allowing individual stereo DACs to be powered off when not in use. The analogue output buffer may also be powered down by setting OUTPD[3:0]. OUTPD[3:0] also switches the analogue outputs VOUTL/R to VMIDDAC to maintain a dc level on the output. Setting AINPD, ADCPD, DACPD[3:0] and OUTPD[3:0] will powerdown everything except the references VMIDADC, ADCREF and VMIDDAC. These may be powered down by setting PDWN. Setting PDWN will override all other powerdown control bits. It is recommended that the 8-channel input mux and buffer, ADC, DAC and output buffers are powered down before setting PDWN. The default is for all powerdown bits to be set except PDWN. w PP Rev 2.0 December 2001 16 WM8771 Product Preview 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 DACDAT is always an input to the WM8771 and ADCDAT is always an output. The default is Slave mode. In Slave mode (MS=0) ADCLRC, DACLRC and BCLK are inputs to the WM8771 (Figure 9). DIN1/2/3/4, ADCLRC and DACLRC are sampled by the WM8771 on the rising edge of BCLK. ADC data is output on DOUT and changes on the falling edge of BCLK. By setting control bit BCLKINV the polarity of BCLK may be reversed so that DIN1/2/3/4, ADCLRC and DACLRC are sampled on the falling edge of BCLK and DOUT changes on the rising edge of BCLK. BCLK ADCLRC WM8771 CODEC DACLRC DSP ENCODER/ DECODER DOUT DIN1/2/3/4 4 Figure 9 Slave Mode In Master mode (MS=1) ADCLRC, DACLRC and BCLK are outputs from the WM8771 (Figure 10). ADCLRC, DACLRC and BITCLK are generated by the WM8771. DIN1/2/3/4 are sampled by the WM8771 on the rising edge of BCLK so the controller must output DAC data that changes on the falling edge of BCLK. ADCDAT is output on DOUT and changes on the falling edge of BCLK. By setting control bit BCLKINV the polarity of BCLK may be reversed so that DIN1/2/3/4 are sampled on the falling edge of BCLK and DOUT changes on the rising edge of BCLK. BCLK ADCLRC WM8771 CODEC DACLRC DSP/ ENCODER/ DECODER DOUT DIN1/2/3/4 4 Figure 10 Master Mode w PP Rev 2.0 December 2001 17 WM8771 Product Preview AUDIO INTERFACE FORMATS Audio data is applied to the internal DAC filters, or output from the ADC filters, via the Digital Audio Interface. 5 popular interface formats are supported: • Left Justified mode • Right Justified mode • I2S mode • DSP Early mode • DSP Late mode All 5 formats send the MSB first and support word lengths of 16, 20, 24 and 32 bits, with the exception of 32 bit right justified mode, which is not supported. In left justified, right justified and I2S modes, the digital audio interface receives DAC data on the DIN1/2/3/4 inputs and outputs ADC data on DOUT. Audio Data for each stereo channel is time multiplexed with ADCLRC/DACLRC indicating whether the left or right channel is present. ADCLRC/DACLRC is also used as a timing reference to indicate the beginning or end of the data words. In left justified, right justified and I2S modes, the minimum number of BCLKs per DACLRC/ADCLRC period is 2 times the selected word length. ADCLRC/DACLRC must be high for a minimum of word length BCLKs and low for a minimum of word length BCLKs. Any mark to space ratio on ADCLRC/DACLRC is acceptable provided the above requirements are met. In DSP early or DSP late mode, all 8 DAC channels are time multiplexed onto DIN1. DACLRC is used as a frame sync signal to identify the MSB of the first word. The minimum number of BCLKs per DACLRC period is 8 times the selected word length. Any mark to space ratio is acceptable on DACLRC provided the rising edge is correctly positioned. The ADC data may also be output in DSP early or late modes, with ADCLRC used as a frame sync to identify the MSB of the first word. The minimum number of BCLKs per ADCLRC period is 2 times the selected word length LEFT JUSTIFIED MODE In left justified mode, the MSB of DIN1/2/3/4 is sampled by the WM8771 on the first rising edge of BCLK following a DACLRC transition. The MSB of the ADC data is output on DOUT and changes on the same falling edge of BCLK as ADCLRC and may be sampled on the rising edge of BCLK. ADCLRC and DACLRC are high during the left samples and low during the right samples (Figure 11). 1/fs LEFT CHANNEL RIGHT CHANNEL DACLRC/ ADCLRC BCLK DIN1/2/3/4/ DOUT 1 MSB 2 3 n-2 n-1 n LSB 1 MSB 2 3 n-2 n-1 n LSB Figure 11 Left Justified Mode TIming Diagram w PP Rev 2.0 December 2001 18 WM8771 Product Preview RIGHT JUSTIFIED MODE In right justified mode, the LSB of DIN1/2/3/4 is sampled by the WM8771 on the rising edge of BCLK preceding a DACLRC transition. The LSB of the ADC data is output on DOUT and changes on the falling edge of BCLK preceding an ADCLRC transition and may be sampled on the rising edge of BCLK. ADCLRC and DACLRC are high during the left samples and low during the right samples (Figure 12). 1/fs LEFT CHANNEL RIGHT CHANNEL DACLRC/ ADCLRC BCLK DIN1/2/3/4/ DOUT 1 2 3 n-2 n-1 MSB n 1 LSB 2 3 n-2 n-1 MSB n LSB Figure 12 Right Justified Mode TIming Diagram I2S MODE In I2S mode, the MSB of DIN1/2/3/4 is sampled by the WM8771 on the second rising edge of BCLK following a DACLRC transition. The MSB of the ADC data is output on DOUT and changes on the first falling edge of BCLK following an ADCLRC transition and may be sampled on the rising edge of BCLK. ADCLRC and DACLRC are low during the left samples and high during the right samples. 1/fs LEFT CHANNEL RIGHT CHANNEL DACLRC/ ADCLRC BCLK 1 BCLK 1 BCLK DIN1/2/3/4/ DOUT 1 2 3 MSB n-2 n-1 n LSB 1 MSB 2 3 n-2 n-1 n LSB Figure 13 I2S Mode TIming Diagram w PP Rev 2.0 December 2001 19 WM8771 Product Preview DSP EARLY MODE In DSP early mode, the MSB of DAC channel 1 left data is sampled by the WM8771 on the second rising edge on BCLK following a DACLRC rising edge. DAC channel 1 right and DAC channels 2, 3 and 4 data follow DAC channel 1 left data (Figure 14). 1 BCLK 1 BCLK 1/fs DACLRC BCK CHANNEL 1 LEFT DIN1 1 2 CHANNEL 1 RIGHT n n-1 MSB 1 2 n-1 CHANNEL 2 LEFT n 1 2 CHANNEL 4 RIGHT n-1 NO VALID DATA n LSB Input Word Length (IWL) Figure 14 DSP Early Mode Timing Diagram – DAC data input The MSB of the left channel ADC data is output on DOUT and changes on the first falling edge of BCLK following a low to high ADCLRC transition and may be sampled on the rising edge of BCLK. The right channel ADC data is contiguous with the left channel data (Figure 15) 1 BCLK 1 BCLK 1/fs ADCLRC BCK LEFT CHANNEL DOUT 1 2 MSB RIGHT CHANNEL n n-1 1 2 n-1 NO VALID DATA n LSB Input Word Length (IWL) Figure 15 DSP Early Mode Timing Diagram – ADC data output w PP Rev 2.0 December 2001 20 WM8771 Product Preview DSP LATE MODE In DSP late mode, the MSB of DAC channel 1 left data is sampled by the WM8771 on the first BCLK rising edge following a DACLRC rising edge. DAC channel 1 right and DAC channels 2, 3 and 4 data follow DAC channel 1 left data (Figure 16). 1/fs DACLRC BCK CHANNEL 1 LEFT DIN1 1 2 CHANNEL 1 RIGHT n n-1 MSB 1 2 n-1 CHANNEL 2 LEFT n 1 2 CHANNEL 4 RIGHT n-1 n NO VALID DATA 1 LSB Input Word Length (IWL) Figure 16 DSP Late Mode Timing Diagram – DAC data input The MSB of the left channel ADC data is output on DOUT and changes on the same falling edge of BCLK as the low to high ADCLRC transition and may be sampled on the rising edge of BCLK. The right channel ADC data is contiguous with the left channel data (Figure 17). 1/fs ADCLRC BCK LEFT CHANNEL DOUT 1 2 MSB RIGHT CHANNEL n n-1 1 2 n-1 NO VALID DATA n 1 LSB Input Word Length (IWL) Figure 17 DSP Late Mode Timing Diagram – ADC data output In both early and late DSP modes, DACL1 is always sent first, followed immediately by DACR1 and the data words for the other 6 channels. No BCLK edges are allowed between the data words. The word order is DAC1 left, DAC1 right, DAC2 left, DAC2 right, DAC3 left, DAC3 right, DAC4 left, DAC4 right. w PP Rev 2.0 December 2001 21 WM8771 Product Preview CONTROL INTERFACE OPERATION The WM8771 is controlled using a 3-wire serial interface in either an SPI compatible configuration or a CCB (Computer Control Bus) configuration. The interface configuration is determined by the state of the CE pin on the rising edge of the RESETB pin. If the CE pin is low on the rising edge of RESETB, CCB configuration is selected. If CE is high on the rising edge of RESETB, SPI compatible configuration is selected. The control interface is 5V tolerant, meaning that the control interface input signals CE, CL and DI may have an input high level of 5V while DVDD is 3V. Input thresholds are determined by DVDD. RESETB and DACMUTE are also 5V tolerant. 3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE DI is used for the program data, CL is used to clock in the program data and CE is used to latch the program data. DI is sampled on the rising edge of CL. The 3-wire interface protocol is shown in Figure 18. CE CL DI B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Figure 18 3-wire SPI compatible Interface 1. B[15:9] are Control Address Bits 2. B[8:0] are Control Data Bits 3. CE is edge sensitive – the data is latched on the rising edge of CE. CCB INTERFACE MODE CCB Interface mode allows multiple devices to be controlled off a common 3-wire bus. Each device on the 3-wire bus has its own identifying address. The WM8771 supports write only CCB interface mode. DI is used for the device address and program data and CL is used to clock in the address and data on DI. DI is sampled on the rising edge of CL. CE indicates whether the data on DI is the device address or program data. The eight clocks before a rising edge on CE will clock in the device address. The device address is latched on the rising edge of CE. The sixteen clocks before a falling edge on CE will clock in the program data. The program data is latched on the falling edge of CE. CE CL DI A0 A1 A2 A3 A4 A5 A6 A7 D0 D1 D2 D3 D14 D15 Figure 19 CCB Interface – CL stopped low w PP Rev 2.0 December 2001 22 WM8771 Product Preview CE CL DI A0 A1 A2 A3 A4 A5 A6 A7 D0 D1 D2 D3 D14 D15 Figure 20 CCB Interface – CL stopped high 1. A[7:0] are Device Address bits 2. D[15:9] are Control Address bits 3. D[8:0] are Control Data bits The address A[7:0] for WM8771 is 8Ch (10001100). CONTROL INTERFACE REGISTERS DIGITAL AUDIO INTERFACE CONTROL REGISTER Interface format is selected via the FMT[1:0] register bits: REGISTER ADDRESS BIT LABEL DEFAULT 10110 Interface Control 1:0 FMT[1:0] 10 DESCRIPTION Interface format Select 00 : right justified mode 01: left justified mode 10: I2S mode 11: DSP (early or late) mode In left justified, right justified or I2S modes, the LRP register bit controls the polarity of ADCLRC/DACLRC. If this bit is set high, the expected polarity of ADCLRC/DACLRC will be the opposite of that shown Figure 11, Figure 12 and Figure 13. Note that if this feature is used as a means of swapping the left and right channels, a 1 sample phase difference will be introduced. In DSP modes, the LRP register bit is used to select between early and late modes. REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 10110 Interface Control 2 LRP 0 In left/right/i2s modes: ADCLRC/DACLRC Polarity (normal) 0 : normal ADCLRC/DACLRC polarity 1: inverted ADCLRC/DACLRC polarity In DSP mode: 0 : Early DSP mode 1: Late DSP mode By default, ADCLRC/DACLRC 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 ADCLRC/DACLRC and DIN1/2/3/4 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 11, Figure 12, Figure 13, Figure 14, Figure 15, Figure 16 and Figure 17. w PP Rev 2.0 December 2001 23 WM8771 Product Preview REGISTER ADDRESS BIT LABEL DEFAULT 10110 Interface Control 3 BCP 0 DESCRIPTION BCLK Polarity (DSP modes) 0 : normal BCLK polarity 1: inverted BCLK polarity The IWL[1:0] bits are used to control the input word length. REGISTER ADDRESS BIT LABEL DEFAULT 10110 Interface Control 5:4 WL[1:0] 10 DESCRIPTION Input Word Length 00 : 16 bit data 01: 20 bit data 10: 24 bit data 11: 32 bit data Note: If 32-bit mode is selected in right justified mode, the WM8771 defaults to 24 bits. In all modes, the data is signed 2's complement. The digital filters always input 24-bit data. If the DAC is programmed to receive 16 or 20 bit data, the WM8771 pads the unused LSBs with zeros. If the DAC is programmed into 32 bit mode, the 8 LSBs are ignored. Note: In 24 bit I2S mode, any width of 24 bits or less is supported provided that ADCLRC/DACLRC is high for a minimum of 24 BCLKs and low for a minimum of 24 BCLKs. A number of options are available to control how data from the Digital Audio Interface is applied to the DAC channels. Control bit MS selects between audio interface Master and Slave Modes. In Master mode ADCLRC, DACLRC and BCLK are outputs and are generated by the WM8771. In Slave mode ADCLRC, DACLRC and BCLK are inputs to WM8771. REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 10111 Interface Control 8 MS 0 Audio Interface Master/Slave Mode select: 0 : Slave Mode 1: Master Mode MASTER MODE ADCLRC/DACLRC FREQUENCY SELECT In Master mode the WM8771 generates ADCLRC, DACLRC and BCLK. These clocks are derived from master clock and the ratio of MCLK to ADCLRC and DACLRC are set by ADCRATE and DACRATE. w REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 10111 ADCLRC and DACLRC frequency select 2:0 ADCRATE[2:0] 010 Master Mode MCLK:ADCLRC ratio select: 000: 128fs 001: 192fs 010: 256fs 011: 384fs 100: 512fs 101: 768fs 6:4 DACRATE[2:0] 010 Master Mode MCLK:DACLRC ratio select: 000: 128fs 001: 192fs 010: 256fs 011: 384fs 100: 512fs 101: 768fs PP Rev 2.0 December 2001 24 WM8771 Product Preview ADC OVERSAMPLING RATE SELECT For ADC operation at 96kHz it is recommended that the user set the ADCOSR bit. This changes the ADC signal processing oversample rate to 64fs. REGISTER ADDRESS BIT LABEL DEFAULT 10111 ADC Oversampling Rate 3 ADCOSR 0 DESCRIPTION ADC oversampling rate select 0: 128x oversampling 1: 64x oversampling MUTE MODES The WM8771 has individual mutes for each of the four DAC channels. Setting MUTE for a channel will apply a ‘soft’ mute to the input of the digital filters of the channel muted. The WM8770 has individual mutes for each of the four DAC channels. Setting MUTE for a channel will apply a ‘soft’ mute to the input of the digital filters of the channel muted. DMUTE[0] mutes DAC channel 1, DMUTE[1] mutes DAC channel 2, DMUTE[2] mutes DAC channel 3 & DMUTE[3] mutes DAC channel 4. REGISTER ADDRESS BIT LABEL DEFAULT 10100 DAC Mute 3:0 DMUTE[3:0] 0 DESCRIPTION DAC Soft Mute select 0 : Normal Operation 1: Soft mute enabled Setting the MUTEALL register bit will apply a 'soft' mute to the input of all the DAC digital filters: REGISTER ADDRESS BIT LABEL DEFAULT 10100 DAC Mute 4 MUTEALL 0 DESCRIPTION Soft Mute select 0 : Normal Operation 1: Soft mute all channels 1.5 1 0.5 0 -0.5 -1 -1.5 -2 -2.5 0 0.001 0.002 0.003 0.004 0.005 0.006 Time(s) Figure 21 Application and Release of Soft Mute w PP Rev 2.0 December 2001 25 WM8771 Product Preview Figure 21 shows the application and release of MUTE whilst a full amplitude sinusoid is being played at 48kHz sampling rate. When MUTE (lower trace) is asserted, the output (upper trace) begins to decay exponentially from the DC level of the last input sample. The output will decay towards VMID with a time constant of approximately 64 input samples. If MUTE is applied to all channels for 1024 or more input samples the outputs will be connected directly to Vmid, if IZD is set. When MUTE is de-asserted, the output will restart immediately from the current input sample. Note that all other means of muting the DAC channels: setting the PL[3:0] bits to 0, setting the PDWN bit or setting attenuation to 0 will cause much more abrupt muting of the output. Each ADC channel also has an individual mute control bit, which mutes the input to the ADC. In addition both channels may be muted by setting ADCMUTE. REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 11001 ADC Mute 7 ADCMUTE 0 ADC MUTE Left and Right 0 : Normal Operation 1: mute ADC left and ADC right 11001 ADC Mute Left 5 MUTE 0 ADC Mute select 0 : Normal Operation 1: mute ADC left 11010 ADC Mute Right 5 MUTE 0 ADC Mute select 0 : Normal Operation 1: mute ADC right The Record outputs may be enabled by setting RECEN[2:0], where RECEN[0] mutes the REC1L and REC1R outputs, RECEN[1] mutes the REC2L and REC2R outputs and RECEN[2] mutes the REC3L and REC3R outputs. REGISTER ADDRESS BIT LABEL DEFAULT 10100 REC Enable [7:5] RECMUTE[2:0] 000 DESCRIPTION REC Output Enable 0 : REC output disabled 1: REC output enabled DE-EMPHASIS MODE A digital De-emphasis filter may be applied to each DAC channel. The De-emphasis filter for each stereo channel is enabled under the control of DEEMP[3:0]. DEEMP[0] enables the de-emphasis filter for channel 1, DEEMP[1] enables the de-emphasis filter for channel 2, DEEMP[2] enables the de-emphasis filter for channel 3 and DEEMP[3] enables the de-emphasis filter for channel 4. REGISTER ADDRESS 10101 DAC De-emphasis Control BIT LABEL DEFAULT [3:0] DEEMPH[3:0] 0000 DESCRIPTION De-emphasis mode select: 0 : Normal Mode 1: De-emphasis Mode Refer to Figure 29, Figure 30, Figure 31, Figure 32, Figure 33 and Figure 34 for details of the DeEmphasis modes at different sample rates. POWERDOWN MODE AND ADC/DAC DISABLE Setting the PDWN register bit immediately powers down the WM8771. All trace of the previous input samples are removed, but all control register settings are preserved. When PDWN is cleared the digital filters will be reinitialised. . It is recommended that the 8-channel input mux and buffer, ADC, DAC and output buffers are powered down before setting PDWN. REGISTER ADDRESS w BIT LABEL DEFAULT DESCRIPTION PP Rev 2.0 December 2001 26 WM8771 Product Preview 11000 Powerdown Control 0 PDWN 0 Power Down Mode Select: 0 : Normal Mode 1: Power Down Mode The ADC and DACs may also be powered down by setting the ADCD and DACD disable bits. Setting ADCD will disable the ADC and select a low power mode. The ADC digital filters will be reset and will reinitialise when ADCD is reset. Each Stereo DAC channel has a separate disable DACD[3:0]. Setting DACD for a channel will disable the DACs and select a low power mode, also connecting the DAC outputs to VMID. Resetting DACD will reinitialise the digital filters. REGISTER ADDRESS BIT LABEL DEFAULT 11000 Powerdown Control 1 ADCD 1 ADC Disable: 0 : Normal Mode 1: Power Down Mode DESCRIPTION 5:2 DACD[3:0] 1 DAC Disable: 0 : Normal Mode 1: Power Down Mode ATTENUATOR 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. REGISTER ADDRESS BIT LABEL DEFAULT 10011 DAC Channel Control 1 ATC 0 DESCRIPTION Attenuator Control Mode: 0 : Right channels use Right attenuations 1: Right Channels use Left attenuations INFINITE ZERO DETECT Setting the IZD register bit will enable the internal infinite zero detect function: REGISTER ADDRESS BIT LABEL DEFAULT 10011 DAC Channel Control 2 IZD 0 DESCRIPTION Infinite zero Mute Enable 0 : disable infinite zero mute 1: enable infinite zero Mute With IZD enabled, applying 1024 consecutive input samples to all 8 DAC channels will cause all outputs to be muted to VMID. Mute will be removed as soon as any channel receives a non-zero input. ZERO FLAG OUTPUT The DZFM control bits allow the selection of the eight DAC channel zero flag bits for output on the ZFLAG1 and ZFLAG2 pins. A ‘1’ on ZFLAG1 or ZFLAG2 indicates 1024 consecutive zero input samples to the channels selected. w REGISTER ADDRESS BIT LABEL DEFAULT 10101 Zero Flag Select 7:4 DZFM[3:0] 0000 DESCRIPTION Selects the output for ZFLG1 and ZFLG2 pins (see Table 9). A ‘1’ indicates 1024 consecutive zero input samples on the channels selected. PP Rev 2.0 December 2001 27 WM8771 Product Preview 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 BIT LABEL DEFAULT 10011 DAC Control 7:4 PL[3:0] 1001 DESCRIPTION PL[3:0] Left Output Right Output 0000 Mute Mute 0001 Left Mute 0010 Right Mute 0011 (L+R)/2 Mute 0100 Mute Left 0101 Left Left 0110 Right Left 0111 (L+R)/2 Left 1000 Mute Right 1001 Left Right 1010 Right Right 1011 (L+R)/2 Right 1100 Mute (L+R)/2 1101 Left (L+R)/2 1110 Right (L+R)/2 1111 (L+R)/2 (L+R)/2 DAC DIGITAL VOLUME CONTROL The DAC volume may be adjusted in the digital domain using independent digital attenuation control registers REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 01001 Digital Attenuation DACL1 7:0 LDA1[7:0] 11111111 (0dB) Digital Attenuation data for Left channel DACL1 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA1 in intermediate latch (no change to output) 1: Store LDA1 and update attenuation on all channels 01010 Digital Attenuation DACR1 7:0 RDA1[6:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR1 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA1 in intermediate latch (no change to output) 1: Store RDA1 and update attenuation on all channels. 01011 Digital Attenuation DACL2 7:0 LDA2[7:0] 11111111 (0dB) 8 UPDATE Not latched w Digital Attenuation data for Left channel DACL2 in 0.5dB steps. See Table 10 Controls simultaneous update of all Attenuation Latches 0: Store LDA2 in intermediate latch (no change to output) 1: Store LDA2 and update attenuation on all channels. PP Rev 2.0 December 2001 28 WM8771 Product Preview REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 01100 Digital Attenuation DACR2 7:0 RDA2[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR2 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA2 in intermediate latch (no change to output) 1: Store RDA2 and update attenuation on all channels. 01101 Digital Attenuation DACL3 7:0 LDA3[7:0] 11111111 (0dB) 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA3 in intermediate latch (no change to output) 1: Store LDA3 and update attenuation on all channels. 01110 Digital Attenuation DACR3 7:0 RDA3[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR3 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA3 in intermediate latch (no change to output) 1: Store RDA3 and update attenuation on all channels. 01111 Digital Attenuation DACL4 7:0 LDA4[7:0] 11111111 (0dB) 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA4 in intermediate latch (no change to output) 1: Store LDA4 and update attenuation on all channels. 10000 Digital Attenuation DACR4 7:0 RDA4[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR4 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA4 in intermediate latch (no change to output) 1: Store RDA4 and update attenuation on all channels. 10001 Master Digital Attenuation (all channels) 7:0 MASTDA[7:0] 11111111 (0dB) Digital Attenuation data for all DAC channels in 0.5dB steps. See Table 10 8 UPDATE Not latched Digital Attenuation data for Left channel DACL3 in 0.5dB steps. See Table 10 Digital Attenuation data for Left channel DACL4 in 0.5dB steps. See Table 10 Controls simultaneous update of all Attenuation Latches 0: Store gain in intermediate latch (no change to output) 1: Store gain and update attenuation on all channels. L/RDAX[7:0] ATTENUATION LEVEL 00(hex) -∞ dB (mute) 01(hex) -127.5dB : : : : : : FE(hex) -0.5dB FF(hex) 0dB Table 10 Digital Volume Control Attenuation Levels The Digital volume control also incorporates a zero cross detect circuit which detects a transition through the zero point before updating the digital volume control with the new volume. This is enabled by control bit DZCEN. w REGISTER ADDRESS BIT LABEL DEFAULT 10011 DAC Control 0 DZCEN 0 DESCRIPTION DAC Digital Volume Zero Cross Enable: 0: Zero cross detect disabled 1: Zero cross detect enabled PP Rev 2.0 December 2001 29 WM8771 Product Preview DAC OUTPUT PHASE The DAC Phase control word determines whether the output of each DAC is non-inverted or inverted REGISTER ADDRESS BIT LABEL DEFAULT 10010 DAC Phase 7:0 PH[7:0] 00000000 DESCRIPTION Bit DAC Phase 0 DAC1L 1 = invert 1 DAC1R 1 = invert 2 DAC2L 1 = invert 3 DAC2R 1 = invert 4 DAC3L 1 = invert 5 DAC3R 1 = invert 6 DAC4L 1 = invert 7 DAC4R 1 = invert ADC GAIN CONTROL Control bits LAG[4:0] and RAG[4:0] control the ADC input gain, allowing the user to attenuate the ADC input signal to match the full-scale range of the ADC. The gain is independently adjustable on left and right inputs. Left and right inputs may also be independently muted. The LRBOTH control bit allows the user to write the same attenuation value to both left and right volume control registers. The ADC volume and mute also applies to the bypass signal path REGISTER ADDRESS BIT LABEL DEFAULT 11001 Attenuation ADCL 4:0 LAG[4:0] 01100 (0dB) 5 MUTE 0 Mute for Left channel ADC: 0: Mute off 1: Mute on 6 LRBOTH 0 Setting LRBOTH will write the same gain value to LAG[4:0] and RAG[4:0] 4:0 RAG[4:0] 01100 (0dB) 5 MUTE 0 Mute for Right channel ADC: 0: Mute off ]1: Mute on 6 LRBOTH 0 Setting LRBOTH will write the same gain value to RAG[4:0] and LAG[4:0] 11010 Attenuation ADCR w DESCRIPTION Attenuation data for Left channel ADC gain in 1dB steps. See Table 11 Attenuation data for right channel ADC gain in 1dB steps. See Table 11 PP Rev 2.0 December 2001 30 WM8771 Product Preview ADC INPUT GAIN Registers LAG and RAG control the left and right channel gain into the stereo ADC in 1dB steps from +19dB to –12dB Table 8 shows how the attenuation levels are selected from the 5-bit words. L/RAG[6:0] ATTENUATION LEVEL 0 -12dB : : 01100 0dB : : 11111 +19dB Table 11 ADC gain control ADC HIGHPASS FILTER DISABLE The ADC digital filters contain a digital highpass filter. This defaults to enabled and can be disabled using software control bit ADCHPD. REGISTER ADDRESS BIT LABEL DEFAULT 10110 ADC control 8 ADCHPD 0 DESCRIPTION ADC Highpass filter disable: 0: Highpass filter enabled 1: Highpass filter disabled ADC INPUT MUX AND POWERDOWN CONTROL REGISTER ADDRESS BIT LABEL DEFAULT DESCRIPTION 11011 ADC mux and powerdown control 2:0 LMX[2:0] 000 ADC left channel input mux control bits (see Figure 35) 6:4 RMX[2:0] 000 ADC right channel input mux control bits (see Figure 35) 8 AINPD 1 Input mux and buffer powerdown 0: Input mux and buffer enabled 1: Input mux and buffer powered down Register bits LMX and RMX control the left and right channel inputs into the stereo ADC. The default is AIN1. However if the analogue input buffer is powered down, by setting AINPD, then all 8-channel mux inputs are switched to buffered VMIDADC. LMX[2:0] LEFT ADC INPUT RMX[2:0] RIGHT ADC INPUT 000 AIN1L 000 AIN1L 001 AIN2L 001 AIN2L 010 AIN3L 010 AIN3L 011 AIN4L 011 AIN4L 100 AIN5L 100 AIN5L 101 AIN6L 101 AIN6L 110 AIN7L 110 AIN7R 111 AIN8L 111 AIN8R Table 12 ADC input mux control w PP Rev 2.0 December 2001 31 WM8771 Product Preview The DAC output buffers can be powered down under control of OUTPD[3:0]. Each stereo channel may be powered down separately. Setting OUTPD[3:0] will power off the output buffer and switch the analogue outputs VOUTL/R to VMIDDAC to maintain a dc level on the output. REGISTER ADDRESS BIT LABEL DEFAULT 11100 Output Powerdown control 8:7 OUTPD[1:0] 11 REGISTER ADDRESS BIT LABEL DEFAULT 11101 Output Powerdown control 8:7 OUTPD[3:2] 11 DESCRIPTION DAC Output Powerdown select 0: output buffer enabled 1: output buffer powered down DESCRIPTION DAC Output Powerdown select 0: output buffer enabled 1: output buffer powered down SOFTWARE REGISTER RESET Writing to register 11111 will cause a register reset, resetting all register bits to their default values. w PP Rev 2.0 December 2001 32 WM8771 Product Preview REGISTER MAP The complete register map is shown below. The detailed description can be found in the relevant text of the device description. These can be controlled using the Control Interface. All unused bits should be set to ‘0’. REGISTER B15 B14 B13 B12 B11 B10 B9 R9(09h) 0 0 0 1 0 0 1 UPDATE LDA1[7:0] X11111111 R10(0Ah) 0 0 0 1 0 1 0 UPDATE RDA1[7:0] X11111111 R11(0Bh) 0 0 0 1 0 1 1 UPDATE LDA2[7:0] X11111111 R12(0Ch) 0 0 0 1 1 0 0 UPDATE RDA2[7:0] X11111111 R13(0Dh) 0 0 0 1 1 0 1 UPDATE LDA3[7:0] X11111111 R14(0Eh) 0 0 0 1 1 1 0 UPDATE RDA3[7:0] X11111111 R15(0Fh) 0 0 0 1 1 1 1 UPDATE LDA4[7:0] X11111111 R16(10h) 0 0 1 0 0 0 0 UPDATE RDA4[7:0] X11111111 R17(11h) 0 0 1 0 0 0 1 UPDATE MASTDA[7:0] X11111111 R18(12h) 0 0 1 0 0 1 0 0 PHASE[8:0] 000000000 R19(13h) 0 0 1 0 0 1 1 0 R20(14h) 0 0 1 0 1 0 0 0 R21(15h) 0 0 1 0 1 0 1 0 R22(16h) 0 0 1 0 1 1 0 ADCHPD 0 R23(17h) 0 0 1 0 1 1 1 MS 0 R24(18h) 0 0 1 1 0 0 0 0 0 0 R25(19h) 0 0 1 1 0 0 1 0 0 LRBOTH MUTE LAG 000001100 R26(1Ah) 0 0 1 1 0 1 0 0 0 LRBOTH MUTE RAG 000001100 R27(1Bh) 0 0 1 1 0 1 1 AINPD 0 R28(1Ch) 0 0 1 1 1 0 0 OUTPD[1:0] 0 0 0 0 0 0 0 110000000 R29i1Dh) 0 0 1 1 1 0 1 OUTPD[3:2] 0 0 0 0 0 0 0 110000000 R31(1Fh) 0 0 1 1 1 1 1 ADDRESS w B8 B7 B6 B5 B4 B3 PL[3:0] 0 RECMUTE[2:0] MUTEALL DZFM[3:0] 0 WL[1:0] BCP DACRATE[2:0] B2 IZD ATC B0 DZCEN DEFAULT 010010000 DMUTE[3:0] 000000000 DEEMP[3:0] 000000000 LRP 000100010 ADCOSR DACD[3:0] RMX B1 0 FMT[1:0] ADCRATE[2:0] 000010010 ADCD 000111110 PWDN LMX 100000000 RESET Not reset DATA DEFAULT PP Rev 2.0 December 2001 33 WM8771 Product Preview 01001 Digital Attenuation DACL1 7:0 LDA1[7:0] 11111111 (0dB) Digital Attenuation data for Left channel DACL1 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA1 in intermediate latch (no change to output) 1: Store LDA1 and update attenuation on all channels 01010 Digital Attenuation DACR1 7:0 RDA1[6:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR1 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA1 in intermediate latch (no change to output) 1: Store RDA1 and update attenuation on all channels. 01011 Digital Attenuation DACL2 7:0 LDA2[7:0] 11111111 (0dB) Digital Attenuation data for Left channel DACL2 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA2 in intermediate latch (no change to output) 1: Store LDA2 and update attenuation on all channels. 01100 Digital Attenuation DACR2 7:0 RDA2[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR2 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA2 in intermediate latch (no change to output) 1: Store RDA2 and update attenuation on all channels. 01101 Digital Attenuation DACL3 7:0 LDA3[7:0] 11111111 (0dB) Digital Attenuation data for Left channel DACL3 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA3 in intermediate latch (no change to output) 1: Store LDA3 and update attenuation on all channels. 01110 Digital Attenuation DACR3 7:0 RDA3[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR3 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA3 in intermediate latch (no change to output) 1: Store RDA3 and update attenuation on all channels. 01111 Digital Attenuation DACL4 7:0 LDA4[7:0] 11111111 (0dB) Digital Attenuation data for Left channel DACL4 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store LDA4 in intermediate latch (no change to output) 1: Store LDA4 and update attenuation on all channels. 10000 Digital Attenuation DACR4 7:0 RDA4[7:0] 11111111 (0dB) Digital Attenuation data for Right channel DACR4 in 0.5dB steps. See Table 10 8 UPDATE Not latched Controls simultaneous update of all Attenuation Latches 0: Store RDA4 in intermediate latch (no change to output) 1: Store RDA4 and update attenuation on all channels. 10001 Master Digital Attenuation (all channels) 7:0 MASTDA[7:0] 11111111 (0dB) Digital Attenuation data for all DAC channels in 0.5dB steps. See Table 10 8 UPDATE Not latched w Controls simultaneous update of all Attenuation Latches 0: Store gain in intermediate latch (no change to output) 1: Store gain and update attenuation on all channels. PP Rev 2.0 December 2001 34 WM8771 Product Preview 10010 Phase swaps 7:0 PHASE 00000000 Controls phase of DAC outputs 0: Sets non inverted output phase 1: inverts phase of DAC output 10011 DAC Control 0 DZCEN 0 DAC Digital Volume Zero Cross Enable: 0: Zero Cross detect disabled 1: Zero Cross detect enabled 1 ATC 0 Attenuator Control 0: All DACs use attenuations as programmed. 1: Right channel DACs use corresponding left DAC attenuations 2 IZD 0 Infinite zero detection circuit control and automute control 0: Infinite zero detect disabled 1: Infinite zero detect enabled 7:4 PL[3:0] 1001 DAC Output Control PL[3:0] 10100 DAC and REC Mute 10101 DAC Control Left Output Right Output PL[3:0] Left Output Right Output 0000 Mute Mute 1000 Mute Right 0001 Left Mute 1001 Left Right 0010 Right Mute 1010 Right Right 0011 (L+R)/2 Mute 1011 (L+R)/2 Right 0100 Mute Left 1100 Mute (L+R)/2 0101 Left Left 1101 Left (L+R)/2 0110 Right Left 1110 Right (L+R)/2 0111 (L+R)/2 Left 1111 (L+R)/2 (L+R)/2 3:0 DMUTE[3:0] 0000 4 MUTEALL 0 7:5 RECEN[2:0] 000 REC output enable 0 : REC outputs muted 1: REC outputs enabled 7:4 DZFM 0000 Selects the ouput for ZFLG1 and ZFLG2 pins (see Table 9). 1: indicates 1024 consecutive zero input samples on the channels selected 0: indicates at least one of selected channels has non zero sample in last 1024 inputs 3:0 DEEMP 0000 De-emphasis mode select: 0 : Normal Mode 1: De-emphasis Mode 1:0 FMT[1:0] 00 w DAC channel soft mute enables: 0: mute disabled 1: mute enabled DAC channel master soft mute. Mutes all DAC channels: 0: mute disabled 1: mute enabled Interface format select PP Rev 2.0 December 2001 35 WM8771 Product Preview 2 LRP 0 ADCLRC/DACLRC Polarity or DSP Early/Late mode select Left Justified / Right Justified / I2S 0: Standard DACLRC Polarity 1: Inverted DACLRC Polarity 10111 Master Mode control 11000 Powerdown Control 11001 Attenuation ADCL DSP Mode 0: Data in-line with ADCLRC/DACLRC 1: Data delayed by 1 BCLK 3 BCP 0 BITCLK Polarity 0: Normal - DIN[3:0], DACLRC & ADCLRC sampled on rising edge of BCLK; DOUT changes on falling edge of BCLK. 1: Inverted - DIN[3:0], DACLRC & ADCLRC sampled on falling edge of BCLK; DOUT changes on rising edge of BCLK. 5:4 WL[1:0] 10 Input Word Length 00: 16-bit Mode 01: 20-bit Mode 10: 24-bit Mode 11: 32-bit Mode (not supported in right justified mode) 8 ADCHPD 0 2:0 ADCRATE[2:0] 010 3 ADCOSR 0 6:4 DACRATE[2:0] 010 8 MS 0 Maser/Slave interface mode select 0: Slave Mode – ADCLRC, DACLRC and BCLK are inputs 1: Master Mode – ADCLRC, DACLRC and BCLK are outputs 0 PWDN 0 Chip Powerdown Control (works in tandem with ADCD and DACD): 1 ADCD 1 ADC powerdown: 5:2 DACD[3:0] 1111 DAC powerdown 4:0 LAG[4:0] 01100 Attenuation data for left channel ADC gain in 1dB steps 5 MUTE 0 Mute for Left channel ADC: 0: Mute off 1: Mute on 6 LRBOTH 0 Setting LRBOTH will write the same gain value to LAG[4:0 and RAG[4:0] w ADC Highpass Filter Disable: 0: Highpass Filter enabled 1: Highpass Filter disabled Master Mode MCLK:ADCLRC ratio select: 000: 128fs 001: 192fs 010: 256fs 011: 384fs 100: 512fs ADC oversample rate select 0: 128x oversampling 1: 64x oversapmling Master Mode MCLK:DACLRC ratio select: 000: 128fs 001: 192fs 010: 256fs 011: 384fs 100: 512fs PP Rev 2.0 December 2001 36 WM8771 Product Preview 7 ADCMUTE 0 4:0 RAG[4:0] 01100 (0dB) 5 MUTE 0 Mute for Right channel ADC: 0: Mute off 1: Mute on 6 LRBOTH 0 Setting LRBOTH will write the same gain value to RAG[4:0 and LAG[4:0] 2:0 LMX[2:0] 000 ADC left channel input mux control bits (see Table 12) 6:4 RMX[2:0] 000 ADC right channel input mux control bits (see Table 12) 8 AINPD 1 Input mux and buffer powerdown 0: Input mux and buffer enabled 1: Input mux and buffer powered down 11100 Output powerdown control 8:7 OUTPD[1:0] 11 DAC Output Powerdown select 0: output buffer enabled 1: output buffer powered down 11101 Output powerdown control 8:7 OUTPD[3:2] 11 DAC Output Powerdown select 0: output buffer enabled 1: output buffer powered down 11111 Software reset [8:0] RESET Not reset 11010 Attenuation ADCR 11011 ADC mux and powerdown control Mute for Left and Right channel ADC: 0: Mute off 1: Mute on Attenuation data for right channel ADC gain in 1dB steps Writing to this register will apply a reset to the device registers. Table 13 Register Map Description w PP Rev 2.0 December 2001 37 WM8771 Product Preview DIGITAL FILTER CHARACTERISTICS PARAMETER TEST CONDITIONS MIN ±0.01 dB 0 TYP MAX UNIT ADC Filter Passband 0.4535fs -6dB 0.5fs ±0.01 Passband ripple Stopband dB 0.5465fs Stopband Attenuation f > 0.5465fs -65 dB Group Delay 22 fs DAC Filter ±0.05 dB Passband 0.444fs -3dB 0.487fs ±0.05 Passband ripple Stopband dB 0.555fs Stopband Attenuation f > 0.555fs -60 dB Group Delay 16 fs Table 14 Digital Filter Characteristics DAC FILTER RESPONSES 0.2 0 0.15 -20 -40 Response (dB) Response (dB) 0.1 -60 0.05 0 -0.05 -80 -0.1 -100 -0.15 -120 -0.2 0 0.5 1 1.5 Frequency (Fs) 2 2.5 3 Figure 22 DAC Digital Filter Frequency Response – 44.1, 48 and 96kHz 0 0.05 0.1 0.15 0.2 0.25 0.3 Frequency (Fs) 0.35 0.4 0.45 0.5 Figure 23 DAC Digital Filter Ripple – 44.1, 48 and 96kHz 0.2 0 0 -0.2 Response (dB) Response (dB) -20 -40 -0.4 -0.6 -60 -0.8 -80 -1 0 0.2 0.4 0.6 Frequency (Fs) 0.8 1 Figure 24 DAC Digital Filter Frequency Response – 192kHz w 0 0.05 0.1 0.15 0.2 0.25 0.3 Frequency (Fs) 0.35 0.4 0.45 0.5 Figure 25 DAC Digital filter Ripple – 192kHz PP Rev 2.0 December 2001 38 WM8771 Product Preview ADC FILTER RESPONSES 0.02 0 0.015 0.01 Response (dB) Response (dB) -20 -40 0.005 0 -0.005 -60 -0.01 -0.015 -80 -0.02 0 0.5 1 1.5 Frequency (Fs) 2 2.5 3 0 0.05 0.1 0.15 0.2 0.25 0.3 Frequency (Fs) 0.35 0.4 0.45 0.5 Figure 27 ADC Digital Filter Ripple Figure 26 ADC Digital Filter Frequency Response ADC HIGH PASS FILTER The WM8771 has a selectable digital highpass filter to remove DC offsets. The filter response is characterised by the following polynomial. H(z) = 1 - z-1 1 - 0.9995z-1 Response (dB) 0 -5 -10 -15 0 0.0005 0.001 Frequency (Fs) 0.0015 0.002 Figure 28 ADC Highpass Filter Response w PP Rev 2.0 December 2001 39 WM8771 Product Preview DIGITAL DE-EMPHASIS CHARACTERISTICS 0 1 0.5 -2 Response (dB) Response (dB) 0 -4 -6 -0.5 -1 -1.5 -2 -8 -2.5 -10 -3 0 2 4 6 8 10 Frequency (kHz) 12 14 16 Figure 29 De-Emphasis Frequency Response (32kHz) 0 2 4 6 8 10 Frequency (kHz) 12 14 16 Figure 30 De-Emphasis Error (32KHz) 0 0.4 0.3 -2 Response (dB) Response (dB) 0.2 -4 -6 0.1 0 -0.1 -0.2 -8 -0.3 -10 -0.4 0 5 10 Frequency (kHz) 15 20 Figure 31 De-Emphasis Frequency Response (44.1KHz) 0 5 10 Frequency (kHz) 15 20 Figure 32 De-Emphasis Error (44.1KHz) 0 1 0.8 -2 0.6 Response (dB) Response (dB) 0.4 -4 -6 0.2 0 -0.2 -0.4 -8 -0.6 -0.8 -10 -1 0 5 10 15 Frequency (kHz) 20 Figure 33 De-Emphasis Frequency Response (48kHz) w 0 5 10 15 Frequency (kHz) 20 Figure 34 De-Emphasis Error (48kHz) PP Rev 2.0 December 2001 40 WM8771 Product Preview EXTERNAL CIRCUIT CONFIGURATION In order to allow the use of 2V rms and larger inputs to the ADC and AUX inputs, a structure is used that uses external resistors to drop these larger voltages. This also increases the robustness of the circuit to external abuse such as ESD pulse. Figure 35 shows the ADC input multiplexor circuit with external components allowing 2Vrms inputs to be applied. 5K AINOPL 10uF 10K 10uF 10K 10uF 10K AINVGL AIN1L AIN2L AIN3L 10uF 10K 10uF 10K AIN7L AIN8L SOURCE SELECTOR INPUTS 5K AINOPR 10uF 10K 10uF 10K 10uF 10K AINVGR AIN1R AIN2R AIN3R 10uF 10K 10uF 10K AIN7R AIN8R Figure 35 ADC input multiplexor confiuration w PP Rev 2.0 December 2001 41 WM8771 Product Preview RECOMMENDED EXTERNAL COMPONENTS 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 high frequency components (the unique low order, high bit count multi-bit sigma delta DAC structure used in WM8771 produces much less high frequency output noise than competitors devices). This filter is typically also used to provide the 2x gain needed to provide the standard 2Vrms output level from most consumer equipment. Figure 24 shows a suitable post DAC filter circuit, with 2x gain. Alternative inverting filter architectures might also be used with as good results. 1.0nF 10uF 1.8kΩ Ω 7.5kΩ Ω 51 VOUT1L Ω 47kΩ 680pF 4.7kΩ Ω 4.7kΩ Ω OP_FIL VOUT1R OP_FIL VOUT2L OP_FIL VOUT2R OP_FIL VOUT3L OP_FIL VOUT3R OP_FIL VOUT4L OP_FIL VOUT4R OP_FIL Figure 36 Recommended post DAC filter circuit w PP Rev 2.0 December 2001 42 WM8771 Product Preview PACKAGE DIMENSIONS FT: 64 PIN TQFP (10 x 10 x 1.0 mm) DM027.A b e 48 33 32 49 E1 E 17 64 Θ 16 1 c D1 L D A A2 A1 -Cccc Symbols A A1 A2 b c D D1 E E1 e L Θ ccc C SEATING PLANE Dimensions (mm) MIN NOM MAX --------1.20 0.05 ----0.15 1.00 1.05 0.95 0.27 0.17 0.22 0.09 ----0.20 12.00 BSC 10.00 BSC 12.00 BSC 10.00 BSC 0.50 BSC 0.45 0.60 0.75 o o o 0 3.5 7 Tolerances of Form and Position 0.08 REF: JEDEC.95, MS-026 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 0.25MM. D. MEETS JEDEC.95 MS-026, VARIATION = ACD. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS. w PP Rev 2.0 December 2001 43 WM8771 Product Preview IMPORTANT NOTICE Wolfson Microelectronics Ltd (WM) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current. All products are sold subject to the WM terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. WM warrants performance of its products to the specifications applicable at the time of sale in accordance with WM’s standard warranty. Testing and other quality control techniques are utilised to the extent WM deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. In order to minimise risks associated with customer applications, adequate design and operating safeguards must be used by the customer to minimise inherent or procedural hazards. WM assumes no liability for applications assistance or customer product design. WM does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of WM covering or relating to any combination, machine, or process in which such products or services might be or are used. WM’s publication of information regarding any third party’s products or services does not constitute WM’s approval, license, warranty or endorsement thereof. Reproduction of information from the WM web site or datasheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations and notices. Representation or reproduction of this information with alteration voids all warranties provided for an associated WM product or service, is an unfair and deceptive business practice, and WM is not responsible nor liable for any such use. Resale of WM’s products or services with statements different from or beyond the parameters stated by WM for that product or service voids all express and any implied warranties for the associated WM product or service, is an unfair and deceptive business practice, and WM is not responsible nor liable for any such use. ADDRESS: Wolfson Microelectronics Ltd 20 Bernard Terrace Edinburgh EH8 9NX United Kingdom Tel :: +44 (0)131 667 9386 Fax :: +44 (0)131 667 5176 Email :: [email protected] w PP Rev 2.0 December 2001 44