WM8746 Wolfson Microelectronics plc, WM8746 Datasheet
WM8746
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WM8746 Summary of contents
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... 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 channels at sample rates from 8 to 192kHz. Additionally WM8746 supports 2 channels at ...
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... WM8746 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 ...
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... WM8746 PIN CONFIGURATION ORDERING INFORMATION TEMPERATURE DEVICE RANGE o WM8746SEDS/V - WM8746SEDS/RV -25 to +85 C Note: Reel quantity = 2,000 w MOISTURE PACKAGE SENSITIVITY LEVEL 28-lead SSOP MSL3 (Pb-free) 28-lead SSOP MSL3 (Pb-free, tape and reel) Production Data PEAK SOLDERING TEMPERATURE 260°C 260°C PD, October 2008, Rev 4 ...
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... WM8746 PIN DESCRIPTION PIN NAME 1 DVDD 2 SCKI Digital input 3 BCKIN Digital input 4 LRCIN Digital input 5 DIN0 Digital input 6 DIN1 Digital input 7 DIN2 Digital input 8 MODE Digital input Internal pull-up 9 MUTE Digital bidirectional 10 LRCIN2 Digital input Internal pull-down 11 DGND 12 ML/I2S Digital input ...
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... WM8746 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 therefore generically susceptible to damage from excessive static voltages ...
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... WM8746 DC ELECTRICAL CHARACTERISTICS PARAMETER Digital supply range Analogue supply range AVDD1 Ground AGND, GR0, GR1, DGND Difference DGND to AGND Analogue supply current Digital supply current Analogue supply current Digital supply current Analogue supply current Digital supply current Note: 1. The digital supply voltages must not exceed the analogue supply voltages. ...
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... WM8746 Test Conditions AVDD = DVDD = 5V, AGND = 0V = DGND = 0V, T PARAMETER Analogue Output Levels Output level Gain mismatch channel-to-channel Minimum resistance load Maximum capacitance load Output d.c. level Power On Reset (POR) POR threshold Notes: 1. Ratio of output level with 1kHz full scale input, to the output level with all zeros into the digital input, measured ‘A’ ...
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... WM8746 MASTER CLOCK TIMING SCKI Figure 1 Master Clock Timing Requirements Test Conditions AVDD = DVDD = 5V, AGND = GR = DGND = 0V, T PARAMETER System Clock Timing Information SCKI System clock pulse width high SCKI System clock pulse width low SCKI System clock cycle time SCKI Duty cycle ...
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... WM8746 DIGITAL CONTROL INTERFACE ML/I2S MC/IWL MD/DM Figure 3 Control Interface Input Timing: 3-Wire Serial Control Mode Test Conditions AVDD = DVDD = 5V, AGND = GR = DGND = 0V, T PARAMETER Program Register Input Information MC/IWL rising edge to ML/I2S rising edge MC/IWL pulse cycle time MC/IWL pulse width low ...
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... DAC. The system clock for WM8746 supports audio sampling rates from 128fs to 768fs, where fs is the audio sampling frequency (LRCIN) typically 32kHz, 44.1kHz, 48kHz, 96kHz or 192kHz. The system clock is used to operate the digital filters and the noise shaping circuits ...
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... Any mark to space ratio on LRCIN is acceptable provided the above requirements are met. The WM8746 will automatically detect when data with a LRCIN period of exactly 32 is sent, and select 16 bit mode - overriding any previously programmed word length. Word length will revert to the previously programmed value if a LRCIN period other than 32 is detected ...
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... WM8746 RIGHT JUSTIFIED MODE In right justified mode, the LSB is sampled on the rising edge of BCKIN preceding a transition. LRCIN is high during the left samples and low during the right samples. LRCIN BCKIN DIN0/1/2 Figure 5 Right Justified Mode Timing Diagram MODE mode, the MSB is sampled on the second rising edge of BCKIN following a LRCIN transition. ...
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... DAC1 left, DAC1 right, DAC2 left, DAC2 right. SPLIT RATE MODE The WM8746 can be used with differing sample rates on the front and rear channels. This allows extremely high quality audio to be played on the front two channels whilst the other channels use normal high quality data streams ...
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... WM8746 MODES OF OPERATION Control of the various modes of operation for the WM8746 is either by software control over the serial interface ,or by hard-wired pin control. Selection of software or hardware mode is via the MODE pin. The following functions may be controlled either via the serial control interface or by hard wiring of the appropriate pins ...
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... Note: If 32-bit mode is selected in right justified mode, the WM8746 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 bit data, the WM8746 pads the unused LSBs with zeros. If the DAC is programmed into 32 bit mode, the 8 LSBs are ignored. ...
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... WM8746 MUTE MODES Setting the MUTE register bit will apply a 'soft' mute to the input of the digital filters: REGISTER ADDRESS 0000010 DAC Channel Control 1.5 1 0.5 0 -0.5 -1 -1.5 -2 -2.5 0 Figure 10 Application and Release of Soft Mute Figure 10 shows the application and release of MUTE whilst a full amplitude sinusoid is being played at 48kHz sampling rate ...
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... WM8746 MUTE PIN Floating A diagram showing how the various MUTE modes interact is shown below in Figure 11. AUTOMUTED (Internal MUTE (Register Bit) Figure 11 Selection Logic for MUTE Modes The MUTE pin behaves as a bi-directional function, that is input to select MUTE or NOT- MUTE output indication of automute operation. MUTE is active high; taking the pin high causes the filters to soft mute, ramping down the audio signal over a few milliseconds ...
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... WM8746 POWERDOWN MODE Setting the PWDN register bit immediately connects all outputs to V mode. All trace of the previous input samples is removed, but all control register settings are preserved. When PWDN is cleared again the first 16 input samples will be ignored as the FIR will repeat it's power-on initialisation sequence ...
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... WM8746 ATTENUATION CONTROL Each DAC channel can be attenuated digitally before being applied to the digital filter. Attenuation is 0dB by default but can be set between 0 and 127.5dB in 0.5dB steps using the 8 Attenuation control bits. All attenuation registers are double latched allowing new values to be pre-latched to several channels before being updated synchronously ...
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... Figure 9. REGISTER ADDRESS 0001001 Split rate mode When the WM8746 receives updates to the volume levels it will, by default, wait for the signal to pass through the V function ensures that minimal distortion is seen on the output when the volume is changed and is applied separately to each channel. ...
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... WM8746 HARDWARE CONTROL MODES When the MODE pin is held high the following hardware modes of operation are available. MUTE AND AUTOMUTE OPERATION Pin 9 (MUTE) controls selection of MUTE directly, and can be used to enable and disable the automute function output of the automuted signal. ...
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... Table 11 Control Interface Mode Selection 3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE The WM8746 can be controlled using a 3-wire serial interface. MD/DM is used for the program data, MC/IWL is used to clock in the program data and ML/I2S is use to latch in the program data. The 3- wire interface protocol is shown in Figure 13. ...
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... WM8746 REGISTER MAP The complete register map is shown below. The detailed description can be found in the relevant text of the device description. There are 9 registers with 9 bits per register. These can be controlled using the Control Interface ...
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... WM8746 REGISTER BIT LABEL ADDRESS 0000010 0 MUTE DAC Control 1 DEEMPH 2 PWDN ATC 3 4 IZD 8:5 PL[3:0] 0000011 1:0 FMT[1:0] Interface Control 2 LRP 3 BCP 5:4 WL[1:0] 8:6 PHASE w DEFAULT 0 Left and Right DACs soft mute control 0: No Mute 1: Mute 0 De-emphasis Control 0: Normal Response (see Figure 14 - Figure 17) 1: De-emphasis Response (see Figure 18 - Figure 23) ...
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... WM8746 REGISTER BIT LABEL ADDRESS 0000100 7:0 L1A[7:0] Attenuation DACL1 8 UPDATE 0000101 7:0 R1A[7:0] Attenuation DACR1 8 UPDATE 0000110 7:0 L2A[7:0] Attenuation DACL2 8 UPDATE 0000111 7:0 R2A[7:0] Attenuation DACR2 8 UPDATE 0001000 7:0 MASTA[7:0] Master Attenuation 8 UPDATE (all channels) 0001001 0 2SPD Extended interface control 1 ZCD Table 13 Register Map Description ...
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... WM8746 DIGITAL FILTER CHARACTERISTICS PARAMETER Passband Stopband Passband Ripple Stopband Attenuation Table 14 Digital Filter Characteristics DAC FILTER RESPONSES 0 -20 -40 -60 -80 -100 -120 0 0.5 1 1.5 Frequency (Fs) Figure 14 DAC Digital Filter Frequency Response – 44.1, 48 and 96kHz 0 -20 -40 -60 -80 0 0.2 0.4 Frequency (Fs) Figure 16 DAC Digital Filter Frequency Response – ...
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... WM8746 DIGITAL DE-EMPHASIS CHARACTERISTICS - Frequency (kHz) Figure 18 De-Emphasis Frequency Response (32kHz - Frequency (kHz) Figure 20 De-Emphasis Frequency Response (44.1kHz - Frequency (kHz) Figure 22 De-Emphasis Frequency Response (48kHz 0.5 0 -0.5 -1 -1 ...
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... WM8746 APPLICATIONS INFORMATION RECOMMENDED EXTERNAL COMPONENTS Figure 24 External Components Diagram RECOMMENDED EXTERNAL COMPONENTS VALUES COMPONENT SUGGESTED REFERENCE VALUE C1 and C5 10µ 0.1µ C11 10µF C12 0.1µF C13 10µF C14 10µF R1 33Ω Table 15 External Components Description w DESCRIPTION De-coupling for DVDD and AVDD1. ...
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... WM8746 DECOUPLING APPLICATIONS INFORMATION SUPPLY PINS DESCRIPTION PIN NAME 1 DVDD 11 DGND 15 AVDD2 16 CAP Analogue output 20 AGND1 24 AGND2 28 AVDD1 DC ELECTRICAL CHARACTERISTICS PARAMETER Analogue supply current Digital supply current Analogue supply current Digital supply current For proper decoupling, 0.1µF surface-mount ceramic capacitors are recommended for AVDD1, AVDD2, DVDD and CAP. Also recommended are 10µ ...
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... WM8746 It is important that the supply pins are connected correctly. If AVDD1 and AVDD2 pins had both been connected to the 10Ω resistor, the performance would be worse. The value of 10Ω is too high and will cause an increase in THD. This is because currents drawn by AVDD1 will affect the reference voltage on AVDD2 ...
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... WM8746 PACKAGE DIMENSIONS 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 10.20 e 0.65 BSC E 7.40 7.80 E 5.00 5. 0.55 0.75 L 1.25 REF 1 θ JEDEC.95, MO-150 REF: 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 0.20MM. ...
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... WM8746 IMPORTANT NOTICE Wolfson Microelectronics plc (“Wolfson”) products and services are sold subject to Wolfson’s terms and conditions of sale, delivery and payment supplied at the time of order acknowledgement. Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the right to make changes to its products and specifications or to discontinue any product or service without notice ...