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             FEATURES D 24-Bit Resolution D Analog Performance: D D D D D D − Dynamic Range: 123 dB − THD+N: 0.0005% Differential Current Output: 4 mA p-p 8× Oversampling Digital Filter: − Stop-Band Attenuation: –98 dB − Pass-Band Ripple: ±0.0002 dB Sampling Frequency: 10 kHz to 200 kHz System Clock: 128, 192, 256, 384, 512, or 768 fS With Autodetect Accepts 16-, 20-, and 24-Bit Audio Data PCM Data Formats: Standard, I2S, and Left-Justified DSD Format Interface Available D D Interface Available for Optional External Digital Filter or DSP D TDMCA or Serial Port (SPI/I2C) D User-Programmable Mode Controls: D D − Digital Attenuation: 0 dB to –120 dB, 0.5 dB/Step − Digital De-Emphasis − Digital Filter Rolloff: Sharp or Slow − Soft Mute − Zero Flag for Each Output Compatible With PCM1792 (Pins and Mode Controls) Dual Supply Operation: − 5-V Analog, 3.3-V Digital D 5-V Tolerant Digital Inputs D Small 28-Lead SSOP Package APPLICATIONS D D D D D D D A/V Receivers SACD Players DVD Players HDTV Receivers Car Audio Systems Digital Multitrack Recorders Other Applications Requiring 24-Bit Audio DESCRIPTION The PCM1796 is a monolithic CMOS integrated circuit that includes stereo digital-to-analog converters and support circuitry in a small 28-lead SSOP package. The data converters use TI’s advanced segment DAC architecture to achieve excellent dynamic performance and improved tolerance to clock jitter. The PCM1796 provides balanced current outputs, allowing the user to optimize analog performance externally. The PCM1796 accepts PCM and DSD audio data formats, providing easy interfacing to audio DSP and decoder chips. The PCM1796 also interfaces with external digital filter devices (DF1704, DF1706, PMD200). Sampling rates up to 200 kHz are supported. A full set of user-programmable functions is accessible through an SPI or I2C serial control port, which supports register write and readback functions. The PCM1796 also supports the time division multiplexed command and audio (TDMCA) data format. This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ORDERING INFORMATION PRODUCT PACKAGE PACKAGE CODE OPERATION TEMPERATURE RANGE PACKAGE MARKING PCM1796DB 28-lead SSOP 28DB –25°C to 85°C PCM1796 ORDERING NUMBER TRANSPORT MEDIA PCM1796DB Tube PCM1796DBR Tape and reel ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range unless otherwise noted(1) PCM1796 VCC1, VCC2L, VCC2R VDD Supply voltage –0.3 V to 6.5 V –0.3 V to 4 V ±0.1 V Supply voltage differences: VCC1, VCC2L, VCC2R ±0.1 V Ground voltage differences: AGND1, AGND2, AGND3L, AGND3R, DGND LRCK, DATA, BCK, SCK, MSEL, RST, MS(2), MDI, MC, MDO(2), ZEROL(2), ZEROR(2) Digital input ZEROL(3), ZEROR(3), MDO(3), MS(3) voltage –0.3 V to 6.5 V –0.3 V to (VDD + 0.3 V) < 4 V –0.3 V to (VCC + 0.3 V) < 6.5 V Analog input voltage ±10 mA Input current (any pins except supplies) Ambient temperature under bias –40°C to 125°C Storage temperature –55°C to 150°C Junction temperature 150°C Lead temperature (soldering) 260°C, 5 s Package temperature (IR reflow, peak) 260°C (1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. (2) Input mode or I2C mode (3) Output mode except for I2C mode ELECTRICAL CHARACTERISTICS all specifications at TA = 25°C, VCC1 = VCC2L = VCC2R = 5 V, VDD = 3.3 V, fS = 44.1 kHz, system clock = 256 fS, and 24-bit data unless otherwise noted PCM1796DB PARAMETER TEST CONDITIONS MIN RESOLUTION TYP MAX 24 UNIT Bits DATA FORMAT (PCM Mode) Audio data interface format Audio data bit length Audio data format fS Sampling frequency System clock frequency Standard, I2S, left-justified 16-, 20-, 24-bit selectable MSB first, twos complement 10 200 kHz 128, 192, 256, 384, 512, 768 fS DATA FORMAT (DSD Mode) Audio data interface format fS 1 Bit Sampling frequency 2.8224 System clock frequency 2 DSD (direct stream digital) Audio data bit length 2.8224 MHz 11.2896 MHz 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ELECTRICAL CHARACTERISTICS (Continued) all specifications at TA = 25°C, VCC1 = VCC2L = VCC2R = 5 V, VDD = 3.3 V, fS = 44.1 kHz, system clock = 256 fS, and 24-bit data unless otherwise noted PCM1796DB PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DIGITAL INPUT/OUTPUT Logic family TTL compatible VIH VIL 2 Input logic level IIH IIL Input logic current VIN = VDD VIN = 0 V VOH VOL Output logic level IOH = –2 mA IOL = 2 mA 0.8 10 –10 2.4 0.4 VDC µA VDC DYNAMIC PERFORMANCE (PCM MODE) (1)(2) THD+N at VOUT = 0 dB fS = 44.1 kHz fS = 96 kHz fS = 192 kHz EIAJ, A-weighted, fS = 44.1 kHz Dynamic range 0.0015% 120 123 123 EIAJ, A-weighted, fS = 192 kHz 123 120 123 EIAJ, A-weighted, fS = 192 kHz 123 fS = 44.1 kHz fS = 96 kHz Level Linearity Error fS = 192 kHz VOUT = –120 dB 116 dB 123 EIAJ, A-weighted, fS = 96 kHz Channel separation 0.001% 0.001% EIAJ, A-weighted, fS = 96 kHz EIAJ, A-weighted, fS = 44.1 kHz Signal-to-noise ratio 0.0005% dB 119 118 dB 117 ±1 dB DYNAMIC PERFORMANCE (MONO MODE) (1)(2)(3) THD+N at VOUT = 0 dB Dynamic range Signal-to-noise ratio fS = 44.1 kHz fS = 96 kHz 0.0005% fS = 192 kHz EIAJ, A-weighted, fS = 44.1 kHz 0.0015% 0.001% 126 EIAJ, A-weighted, fS = 96 kHz 126 EIAJ, A-weighted, fS = 192 kHz 126 EIAJ, A-weighted, fS = 44.1 kHz 126 EIAJ, A-weighted, fS = 96 kHz EIAJ, A-weighted, fS = 192 kHz 126 dB dB 126 (1) Filter condition: THD+N: 20-Hz HPF, 20-kHz AES17 LPF Dynamic range: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Signal-to-noise ratio: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Channel separation: 20-Hz HPF, 20-kHz AES17 LPF Analog performance specifications are measured using the System Twot Cascade audio measurement system by Audio Precision in the averaging mode. (2) Dynamic performance and dc accuracy are specified at the output of the postamplifier as shown in Figure 36. (3) Dynamic performance and dc accuracy are specified at the output of the measurement circuit as shown in Figure 38. Audio Precision and System Two are trademarks of Audio Precision, Inc. Other trademarks are the property of their respective owners. 3 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ELECTRICAL CHARACTERISTICS (Continued) all specifications at TA = 25°C, VCC1 = VCC2L = VCC2R = 5 V, VDD = 3.3 V, fS = 44.1 kHz, system clock = 256 fS, and 24-bit data unless otherwise noted PCM1796DB PARAMETER TEST CONDITIONS MIN TYP UNIT MAX DSD MODE DYNAMIC PERFORMANCE (1) (2) (44.1 kHZ, 64 fS) THD+N at FS 2 V rms Dynamic range –60 dB, EIAJ, A-weighted 0.0007% 122 dB Signal-to-noise ratio EIAJ, A-weighted 122 dB ANALOG OUTPUT Gain error –7 ±2 7 % of FSR Gain mismatch, channel-to-channel –3 ±0.5 3 % of FSR –2 ±0.5 2 % of FSR Bipolar zero error At BPZ Output current Full scale (0 dB) Center current At BPZ 4 mA p-p –3.5 mA DIGITAL FILTER PERFORMANCE ±0.1 De-emphasis error dB FILTER CHARACTERISTICS–1: SHARP ROLLOFF Pass band ±0.0002 dB 0.454 fS –3 dB Stop band 0.49 fS 0.546 fS ±0.0002 Pass-band ripple Stop-band attenuation Stop band = 0.546 fS –98 Delay time dB dB 38/fS s FILTER CHARACTERISTICS–2: SLOW ROLLOFF Pass band ±0.001 dB 0.21 fS –3 dB Stop band 0.448 fS 0.79 fS ±0.001 Pass-band ripple Stop-band attenuation Delay time Stop band = 0.732 fS –80 dB dB s (1) Filter condition: THD+N: 20-Hz HPF, 20-kHz AES17 LPF Dynamic range: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Signal-to-noise ratio: 20-Hz HPF, 20-kHz AES17 LPF, A-weighted Channel separation: 20-Hz HPF, 20-kHz AES17 LPF Analog performance specifications are measured using the System Two Cascade audio measurement system by Audio Precision in the averaging mode. (2) Dynamic performance and dc accuracy are specified at the output of the postamplifier as shown in Figure 37. 4 38/fS 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ELECTRICAL CHARACTERISTICS (Continued) all specifications at TA = 25°C, VCC1 = VCC2L = VCC2R = 5 V, VDD = 3.3 V, fS = 44.1 kHz, system clock = 256 fS, and 24-bit data unless otherwise noted PCM1796DB PARAMETER TEST CONDITIONS MIN TYP UNIT MAX POWER SUPPLY REQUIREMENTS VDD VCC1 VCC2L VCC2R Voltage range 3 3.3 3.6 VDC 4.75 5 5.25 VDC 7 9 fS = 44.1 kHz fS = 96 kHz IDD Supply current (1) ICC Power dissipation (1) 13 fS = 192 kHz fS = 44.1 kHz 25 fS = 96 kHz fS = 192 kHz 19 18 mA 23 mA 20 fS = 44.1 kHz fS = 96 kHz 140 115 fS = 192 kHz 180 150 mW TEMPERATURE RANGE Operation temperature –25 θJA Thermal resistance (1) Input is BPZ data. 28-pin SSOP 85 100 °C °C/W PIN ASSIGNMENTS PCM1796 (TOP VIEW) ZEROL ZEROR MSEL LRCK DATA BCK SCK DGND VDD MS MDI MC MDO RST 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 VCC2L AGND3L IOUTL– IOUTL+ AGND2 VCC1 VCOML VCOMR IREF AGND1 IOUTR– IOUTR+ AGND3R VCC2R 5 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Terminal Functions TERMINAL NAME PIN I/O DESCRIPTIONS AGND1 19 – Analog ground (internal bias) AGND2 24 – Analog ground (internal bias) AGND3L 27 – Analog ground (L-channel DACFF) AGND3R 16 – BCK 6 I Analog ground (R-channel DACFF) Bit clock input(1) DATA 5 I Serial audio data input(1) DGND 8 – Digital ground IOUTL+ IOUTL– 25 O L-channel analog current output+ 26 O L-channel analog current output– IOUTR+ IOUTR– 17 O R-channel analog current output+ 18 O R-channel analog current output– IREF LRCK 20 – 4 I Output current reference bias pin Left and right clock (fS) input(1) MC 12 I Mode control clock input(1) Mode control data input(1) MDI 11 I MDO 13 I/O MS 10 I/O MSEL 3 I RST 14 I I2C/SPI select(1) Reset(1) SCK 7 I System clock input(1) VCC1 VCC2L 23 – Analog power supply, 5 V 28 – Analog power supply (L-channel DACFF), 5 V VCC2R VCOML 15 – Analog power supply (R-channel DACFF), 5 V 22 – L-channel internal bias decoupling pin VCOMR VDD 21 – R-channel internal bias decoupling pin 9 – ZEROL 1 I/O Digital power supply, 3.3 V Zero flag for L-channel(2) Mode control readback data output(3) Mode control chip-select input(2) ZEROR 2 I/O Zero flag for R-channel(2) (1) Schmitt-trigger input, 5-V tolerant (2) Schmitt-trigger input and output. 5-V tolerant input and CMOS output (3) Schmitt-trigger input and output. 5-V tolerant input. In I2C mode, this pin becomes an open-drain 3-state output; otherwise, this pin is a CMOS output. 6 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 FUNCTIONAL BLOCK DIAGRAM IOUTL– LRCK BCK Current Segment DAC Audio Data Input I/F RST IOUTL+ 8 Oversampling Digital Filter and Function Control MDO MDI VCOML Advanced Segment DAC Modulator Bias and Vref MC IREF VCOMR Current Segment DAC MSEL VOUTR IOUTR+ I/V and Filter System Clock Manager VCC2R VCC1 AGND3L AGND2 AGND1 VDD Power Supply DGND Zero Detect SCK ZEROL ZEROR I/V and Filter IOUTR– Function Control I/F AGND3R MS VOUTL VCC2L DATA 7 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 TYPICAL PERFORMANCE CURVES DIGITAL FILTER Digital Filter Response AMPLITUDE vs FREQUENCY AMPLITUDE vs FREQUENCY 0 5 0.0005 0.0004 4 −20 3 0.0003 −40 Amplitude – dB Amplitude – dB 2 0.0002 −60 −80 −100 1 0.0001 0 −1 –0.0001 −2 –0.0002 −120 −3 –0.0003 −140 −4 –0.0004 −160 0 1 2 3 4 −5 –0.0005 0.0 0.1 Frequency [× fS] 0.2 0.3 0.4 0.5 Frequency [× fS] Figure 1. Frequency Response, Sharp Rolloff Figure 2. Pass-Band Ripple, Sharp Rolloff AMPLITUDE vs FREQUENCY AMPLITUDE vs FREQUENCY 0 0 −2 −20 −4 −40 Amplitude – dB Amplitude – dB −6 −60 −80 −100 −8 −10 −12 −14 −120 −16 −140 −18 −160 0 1 2 3 4 Frequency [× fS] Figure 3. Frequency Response, Slow Rolloff 8 −20 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Frequency [× fS] Figure 4. Transition Characteristics, Slow Rolloff 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 De-Emphasis Filter DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 0.5 fS = 32 kHz −1 0.3 De-Emphasis Error – dB −2 De-Emphasis Level – dB fS = 32 kHz 0.4 −3 −4 −5 −6 −7 0.2 0.1 −0.0 0.0 −0.1 −0.2 −8 −0.3 −9 −0.4 −10 −0.5 0 2 4 6 8 10 12 14 0 2 4 6 f – Frequency – kHz Figure 5 10 12 14 Figure 6 DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 0.5 fS = 44.1 kHz −1 fS = 44.1 kHz 0.4 0.3 De-Emphasis Error – dB −2 De-Emphasis Level – dB 8 f – Frequency – kHz −3 −4 −5 −6 −7 0.2 0.1 −0.0 0.0 −0.1 −0.2 −8 −0.3 −9 −0.4 −10 −0.5 0 2 4 6 8 10 12 14 f – Frequency – kHz Figure 7 16 18 20 0 2 4 6 8 10 12 14 16 18 20 f – Frequency – kHz Figure 8 9 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 De-Emphasis Filter (Continued) DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 0.5 fS = 48 kHz −1 0.3 De-Emphasis Error – dB De-Emphasis Level – dB −2 −3 −4 −5 −6 −7 0.2 0.1 −0.0 0.0 −0.1 −0.2 −8 −0.3 −9 −0.4 −10 −0.5 0 2 4 6 8 10 12 14 f – Frequency – kHz Figure 9 10 fS = 48 kHz 0.4 16 18 20 22 0 2 4 6 8 10 12 14 f – Frequency – kHz Figure 10 16 18 20 22 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ANALOG DYNAMIC PERFORMANCE Supply Voltage Characteristics TOTAL HARMONIC DISTORTION + NOISE vs SUPPLY VOLTAGE DYNAMIC RANGE vs SUPPLY VOLTAGE 126 124 fS = 96 kHz Dynamic Range – dB THD+N – Total Harmonic Distortion + Noise – % 0.01 0.001 fS = 192 kHz fS = 48 kHz 4.75 5.00 5.25 fS = 192 kHz 120 118 fS = 96 kHz 0.0001 4.50 116 4.50 5.50 VCC – Supply Voltage – V 5.00 5.25 5.50 Figure 12 SIGNAL-to-NOISE RATIO vs SUPPLY VOLTAGE CHANNEL SEPARATION vs SUPPLY VOLTAGE 126 122 fS = 96 kHz 124 122 fS = 48 kHz fS = 96 kHz 120 Channel Separation – dB SNR – Signal-to-Noise Ratio – dB 4.75 VCC – Supply Voltage – V Figure 11 fS = 192 kHz 120 118 116 4.50 fS = 48 kHz 122 118 fS = 48 kHz fS = 192 kHz 116 114 4.75 5.00 5.25 5.50 VCC – Supply Voltage – V Figure 13 112 4.50 4.75 5.00 5.25 5.50 VCC – Supply Voltage – V Figure 14 NOTE: PCM mode, TA = 25°C, VDD = 3.3 V, measurement circuit is Figure 36. 11 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Temperature Characteristics TOTAL HARMONIC DISTORTION + NOISE vs FREE-AIR TEMPERATURE DYNAMIC RANGE vs FREE-AIR TEMPERATURE 126 124 Dynamic Range – dB THD+N – Total Harmonic Distortion + Noise – % 0.01 fS = 96 kHz 0.001 fS = 192 kHz fS = 48 kHz fS = 96 kHz fS = 48 kHz 122 fS = 192 kHz 120 118 0.0001 −50 −25 0 25 50 75 116 −50 100 TA – Free-Air Temperature – °C −25 Figure 15 124 120 fS = 96 kHz Channel Separation – dB SNR – Signal-to-Noise Ratio – dB 122 fS = 48 kHz 120 118 116 −50 75 100 75 100 fS = 96 kHz fS = 192 kHz 118 fS = 48 kHz 116 114 −25 0 25 50 75 100 TA – Free-Air Temperature – °C Figure 17 NOTE: PCM mode, VDD = 3.3 V, VCC = 5 V, measurement circuit is Figure 36. 12 50 CHANNEL SEPARATION vs FREE-AIR TEMPERATURE 126 fS = 192 kHz 25 Figure 16 SIGNAL-to-NOISE RATIO vs FREE-AIR TEMPERATURE 122 0 TA – Free-Air Temperature – °C 112 −50 −25 0 25 50 TA – Free-Air Temperature – °C Figure 18 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 AMPLITUDE vs FREQUENCY 0 0 −20 −20 −40 −40 Amplitude – dB Amplitude – dB AMPLITUDE vs FREQUENCY −60 −80 −100 −60 −80 −100 −120 −120 −140 −140 −160 −160 0 2 4 6 8 10 12 14 16 18 20 0 10 20 f – Frequency – kHz 40 50 60 70 80 90 100 f – Frequency – kHz NOTE: PCM mode, fS = 48 kHz, 32768 point 8 average, TA = 25°C, VDD = 3.3 V VCC = 5 V, measurement circuit is Figure 36. Figure 19. –60-dB Output Spectrum, BW = 20 kHz NOTE: PCM mode, fS = 96 kHz, 32768 point 8 average, TA = 25°C, VDD = 3.3 V VCC = 5 V, measurement circuit is Figure 36. Figure 20. –60-dB Output Spectrum, BW = 100 kHz AMPLITUDE vs FREQUENCY TOTAL HARMONIC DISTORTION + NOISE vs INPUT LEVEL 0 10 −20 1 −40 Amplitude – dB THD+N – Total Harmonic Distortion + Noise – % 30 0.1 0.01 −60 −80 −100 −120 0.001 −140 0.0001 −90 −80 −70 −60 −50 −40 −30 −20 −10 −160 0 Input Level – dBFS 0 2 4 6 8 10 12 14 16 18 20 f – Frequency – kHz NOTE: PCM mode, fS = 48 kHz, TA = 25°C, VDD = 3.3 V, VCC = 5 V, NOTE: DSD mode (FIR-2), 32768 point 8 average, TA = 25°C, measurement circuit is Figure 36. VDD = 3.3 V, VCC = 5 V, measurement circuit is Figure 37. Figure 21. THD+N vs Input Level, PCM Mode Figure 22. –60-dB Output Spectrum, DSD Mode 13 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 SYSTEM CLOCK AND RESET FUNCTIONS System Clock Input The PCM1796 requires a system clock for operating the digital interpolation filters and advanced segment DAC modulators. The system clock is applied at the SCK input (pin 7). The PCM1796 has a system clock detection circuit that automatically senses the frequency at which the system clock is operating. Table 1 shows examples of system clock frequencies for common audio sampling rates. If the oversampling rate of the delta-sigma modulator is selected as 128 fS, the system clock frequency is required to be over 256 fS. Figure 23 shows the timing requirements for the system clock input. For optimal performance, it is important to use a clock source with low phase jitter and noise. One of the Texas Instruments PLL1700 family of multiclock generators is an excellent choice for providing the PCM1796 system clock. Table 1. System Clock Rates for Common Audio Sampling Frequencies SAMPLING FREQUENCY SYSTEM CLOCK FREQUENCY (fSCK) (MHz) 128 fS 4.096(1) 192 fS 6.144(1) 256 fS 8.192 12.288 16.384 24.576 8.4672 11.2896 16.9344 22.5792 33.8688 48 kHz 5.6488(1) 6.144(1) 9.216 12.288 18.432 96 kHz 12.288 18.432 24.576 49.152(1) 36.864 73.728(1) 24.576 49.152(1) —(2) 36.864 73.728(1) —(2) 32 kHz 44.1 kHz 192 kHz 24.576 36.864 (1) This system clock rate is not supported in I2C fast mode. (2) This system clock rate is not supported for the given sampling frequency. 384 fS 512 fS 768 fS t(SCKH) H 2V System Clock (SCK) 0.8 V L t(SCKL) PARAMETERS t(SCY) MIN UNITS 13 ns 0.4t(SCY) ns t(SCKL) System clock pulse duration, LOW 0.4t(SCY) ns Figure 23. System Clock Input Timing 14 MAX t(SCY) System clock pulse cycle time t(SCKH) System clock pulse duration, HIGH 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Power-On and External Reset Functions The PCM1796 includes a power-on reset function. Figure 24 shows the operation of this function. With VDD > 2 V, the power-on reset function is enabled. The initialization sequence requires 1024 system clocks from the time VDD > 2 V. After the initialization period, the PCM1796 is set to its default reset state, as described in the MODE CONTROL REGISTERS section of this data sheet. The PCM1796 also includes an external reset capability using the RST input (pin 14). This allows an external controller or master reset circuit to force the PCM1796 to initialize to its default reset state. Figure 25 shows the external reset operation and timing. The RST pin is set to logic 0 for a minimum of 20 ns. The RST pin is then set to a logic 1 state, thus starting the initialization sequence, which requires 1024 system clock periods. The external reset is especially useful in applications where there is a delay between the PCM1796 power up and system clock activation. VDD 2.4 V (Max) 2 V (Typ) 1.6 V (Min) Reset Reset Removal Internal Reset 1024 System Clocks System Clock Figure 24. Power-On Reset Timing RST (Pin 14) 1.4 V t(RST) Reset Reset Removal Internal Reset 1024 System Clocks System Clock t(RST) PARAMETERS MIN Reset pulse duration, LOW 20 MAX UNITS ns Figure 25. External Reset Timing 15 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 AUDIO DATA INTERFACE Audio Serial Interface The audio interface port is a 3-wire serial port. It includes LRCK (pin 4), BCK (pin 6), and DATA (pin 5). BCK is the serial audio bit clock, and it is used to clock the serial data present on DATA into the serial shift register of the audio interface. Serial data is clocked into the PCM1796 on the rising edge of BCK. LRCK is the serial audio left/right word clock. The PCM1796 requires the synchronization of LRCK and system clock, but does not need a specific phase relation between LRCK and system clock. If the relationship between LRCK and system clock changes more than ±6 BCK, internal operation is initialized within 1/fS and analog outputs are forced to the bipolar zero level until resynchronization between LRCK and system clock is completed. PCM Audio Data Formats and Timing The PCM1796 supports industry-standard audio data formats, including standard right-justified, I2S, and left-justified. The data formats are shown in Figure 27. Data formats are selected using the format bits, FMT[2:0], in control register 18. The default data format is 24-bit I2S. All formats require binary 2s complement, MSB-first audio data. Figure 26 shows a detailed timing diagram for the serial audio interface. 1.4 V LRCK t(BCH) t(BCL) t(LB) 1.4 V BCK t(BCY) t(BL) 1.4 V DATA t(DS) t(DH) PARAMETERS MIN UNITS BCK pulse cycle time 70 ns BCK pulse duration, LOW 30 ns t(BCH) t(BL) BCK pulse duration, HIGH 30 ns BCK rising edge to LRCK edge 10 ns t(LB) t(DS) LRCK edge to BCK rising edge 10 ns DATA setup time 10 ns t(DH) — DATA hold time 10 ns LRCK clock data 50% ± 2 bit clocks Figure 26. Timing of Audio Interface 16 MAX t(BCY) t(BCL) 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 (1) Standard Data Format (Right-Justified); L-Channel = HIGH, R-Channel = LOW 1/fS LRCK R-Channel L-Channel BCK Audio Data Word = 16-Bit DATA 14 15 16 1 2 MSB 15 16 1 2 15 16 LSB Audio Data Word = 20-Bit DATA 18 19 20 1 2 19 20 1 2 19 20 LSB MSB Audio Data Word = 24-Bit DATA 22 23 24 1 2 23 24 1 2 23 24 LSB MSB (2) Left-Justified Data Format; L-Channel = HIGH, R-Channel = LOW 1/fS LRCK R-Channel L-Channel BCK Audio Data Word = 24-Bit DATA 1 2 23 24 1 2 23 24 1 2 LSB MSB (3) I2S Data Format; L-Channel = LOW, R-Channel = HIGH 1/fS LRCK L-Channel R-Channel BCK Audio Data Word = 16-Bit DATA 1 2 15 16 MSB 1 2 1 2 15 16 1 2 1 2 LSB Audio Data Word = 24-Bit DATA 1 2 23 24 MSB 23 24 LSB Figure 27. Audio Data Input Formats 17 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 External Digital Filter Interface and Timing The PCM1796 supports an external digital filter interface comprising a 3- or 4-wire synchronous serial port, which allows the use of an external digital filter. External filters include the Texas Instruments’ DF1704 and DF1706, the Pacific Microsonics PMD200, or a programmable digital signal processor. In the external DF mode, LRCK (pin 4), BCK (pin 6) and DATA (pin 5) are defined as WDCK, the word clock; BCK, the bit clock; and DATA, the monaural data. The external digital filter interface is selected by using the DFTH bit of control register 20, which functions to bypass the internal digital filter of the PCM1796. When the DFMS bit of control register 19 is set, the PCM1796 can process stereo data. In this case, ZEROL (pin 1) and ZEROR (pin 2) are defined as L-channel data and R-channel data input, respectively. Detailed information for the external digital filter interface mode is provided in the APPLICATION FOR EXTERNAL DIGITAL FILTER INTERFACE section of this data sheet. Direct Stream Digital (DSD) Format Interface and Timing The PCM1796 supports the DSD format interface operation, which includes out-of-band noise filtering using an internal analog FIR filter. For DSD operation, SCK (pin 7) is redefined as BCK, DATA (pin 5) as DATAL (left channel audio data), and LRCK (pin 4) as DATAR (right channel audio data). BCK (pin 6) must be forced low in the DSD mode. The DSD format interface is activated by setting the DSD bit of control register 20. Detailed information for the DSD mode is provided in the APPLICATION FOR DSD FORMAT (DSD MODE) INTERFACE section of this data sheet. TDMCA Interface The PCM1796 supports the time-division-multiplexed command and audio (TDMCA) data format to enable control of and communication with a number of external devices over a single serial interface. Detailed information for the TDMCA format is provided in the TDMCA INTERFACE FORMAT section of this data sheet. FUNCTION DESCRIPTIONS Zero Detect The PCM1796 has a zero-detect function. When the PCM1796 detects the zero conditions as shown in Table 2, the PCM1796 sets ZEROL (pin 1) and ZEROR (pin 2) to HIGH. Table 2. Zero Conditions MODE PCM DATA is continuously LOW for 1024 LRCKs. External DF Mode DATA is continuously LOW for 1024 WDCKs. DZ0 There are an equal number of 1s and 0s in every 8 bits of DSD input data for 23 ms. DZ1 The input data is 1001 0110 continuously for 23 ms. DSD 18 DETECTING CONDITION AND TIME 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 SERIAL CONTROL INTERFACE The PCM1796 supports SPI and I2C that sets mode control registers as shown in Table 4. This serial control interface is selected by MSEL (pin 3), SPI is activated when MSEL is set to LOW, and I2C is activated when MSEL is set to HIGH. SPI Interface The SPI interface is a 4-wire synchronous serial port that operates asynchronously to the serial audio interface and the system clock (SCK). The serial control interface is used to program and read the on-chip mode registers. The control interface includes MDO (pin 13), MDI (pin 11), MC (pin 12), and MS (pin 10). MDO is the serial data output, used to read back the values of the mode registers; MDI is the serial data input, used to program the mode registers; MC is the serial bit clock, used to shift data in and out of the control port, and MS is the mode control enable, used to enable the internal mode register access. Register Read/Write Operation All read/write operations for the serial control port use 16-bit data words. Figure 28 shows the control data word format. The most significant bit is the read/write (R/W) bit. For write operations, the R/W bit must be set to 0. For read operations, the R/W bit must be set to 1. There are seven bits, labeled IDX[6:0], that hold the register index (or address) for the read and write operations. The least significant eight bits, D[7:0], contain the data to be written to, or the data that was read from, the register specified by IDX[6:0]. Figure 29 shows the functional timing diagram for writing or reading the serial control port. MS is held at a logic 1 state until a register needs to be written or read. To start the register write or read cycle, MS is set to logic 0. Sixteen clocks are then provided on MC, corresponding to the 16 bits of the control data word on MDI and readback data on MDO. After the eighth clock cycle has completed, the data from the indexed-mode control register appears on MDO during the read operation. After the sixteenth clock cycle has completed, the data is latched into the indexed-mode control register during the write operation. To write or read subsequent data, MS must be set to 1 once. LSB MSB R/W IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 D7 D6 D5 Register Index (or Address) D4 D3 D2 D1 D0 Register Data Figure 28. Control Data Word Format for MDI MS MC MDI MDO R/W A6 A5 A4 A3 High Impedance A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 When Read Mode is Instructed NOTE: Bit 15 is used for selection of write or read. Setting R/W = 0 indicates a write, while R/W = 1 indicates a read. Bits 14–8 are used for the register address. Bits 7–0 are used for register data. Figure 29. Serial Control Format 19 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 t(MHH) MS 1.4 V t(MSS) t(MCL) t(MCH) t(MSH) MC 1.4 V t(MCY) LSB MDI t(MDS) 1.4 V t(MOS) t(MDH) MDO 50% of VDD PARAMETER t(MCY) t(MCL) MC pulse cycle time t(MCH) t(MHH) t(MSS) t(MSH) t(MDH) t(MDS) MIN MAX ns MC low-level time 40 ns MC high-level time 40 ns MS high-level time 80 ns MS falling edge to MC rising edge MS hold time(1) 15 ns 15 ns MDI hold time 15 ns MDI setup time 15 t(MOS) MC falling edge to MDO stable (1) MC rising edge for LSB to MS rising edge Figure 30. Control Interface Timing 20 UNITS 100 ns 30 ns 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 I2C INTERFACE The PCM1796 supports the I2C serial bus and the data transmission protocol for standard and fast mode as a slave device. This protocol is explained in I2C specification 2.0. In I2C mode, the control terminals are changed as follows. TERMINAL NAME TDMCA NAME PROPERTY DESCRIPTION I2C address 0 MS ADR0 Input MDI ADR1 Input MC SCL Input I2C address 1 I2C clock MDO SDA Input/output I2C data Slave Address MSB LSB 1 0 0 1 1 ADR1 ADR0 R/W The PCM1796 has 7 bits for its own slave address. The first five bits (MSBs) of the slave address are factory preset to 10011. The next two bits of the address byte are the device select bits which can be user-defined by the ADR1 and ADR0 terminals. A maximum of four PCM1796s can be connected on the same bus at one time. Each PCM1796 responds when it receives its own slave address. Packet Protocol A master device must control packet protocol, which consists of start condition, slave address, read/write bit, data if write or acknowledge if read, and stop condition. The PCM1796 supports only slave receivers and slave transmitters. SDA SCL St 1−7 8 9 1−8 9 1−8 9 9 Slave Address R/W ACK DATA ACK DATA ACK ACK R/W: Read Operation if 1; Otherwise, Write Operation ACK: Acknowledgement of a Byte if 0 NACK: Not Acknowledgement if 1 DATA: 8 Bits (Byte) Start Condition Write Operation Sp Stop Condition Transmitter M M M S M S M S S M Data Type St Slave Address W ACK DATA ACK DATA ACK ACK Sp Read Operation Transmitter M M M S S M S M M M Data Type St Slave Address R ACK DATA ACK DATA ACK NACK Sp M: Master Device S: Slave Device St: Start Condition Sp: Stop Condition W: Write R: Read ACK: Acknowledge NACK: Not Acknowledge Figure 31. Basic I2C Framework 21 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Write Register A master can write to any PCM1796 registers using single or multiple accesses. The master sends a PCM1796 slave address with a write bit, a register address, and the data. If multiple access is required, the address is that of the starting register, followed by the data to be transferred. When the data are received properly, the index register is incremented by 1 automatically. When the index register reaches 0x7F, the next value is 0x00. When undefined registers are accessed, the PCM1796 does not send an acknowledgement. Figure 32 is a diagram of the write operation. Transmitter M M M S M S M S M S S M Data Type St Slave Address W ACK Reg Address ACK Write Data 1 ACK Write Data 2 ACK ACK Sp M: Master Device S: Slave Device St: Start Condition Sp: Stop Condition ACK: Acknowledge W: Write Figure 32. Write Operation Read Register A master can read the PCM1796 register. The value of the register address is stored in an indirect index register in advance. The master sends a PCM1796 slave address with a read bit after storing the register address. Then the PCM1796 transfers the data which the index register points to. When the data are transferred during a multiple access, the index register is incremented by 1 automatically. (When first going into read mode immediately following a write, the index register is not incremented. The master can read the register that was previously written.) When the index register reaches 0x7F, the next value is 0x00. The PCM1796 outputs some data when the index register is 0x10 to 0x1F, even if it is not defined in Table 4. Figure 33 is a diagram of the read operation. Transmitter M M M Data Type St Slave Address W S M S ACK Reg Address ACK M M M S S M M M Sr Slave Address R ACK Data ACK NACK Sp M: Master Device S: Slave Device St: Start Condition Sr: Repeated Start Condition Sp: Stop Condition W: Write R: Read Figure 33. Read Operation 22 ACK: Acknowledge NACK: Not Acknowledge 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Noise Suppression The PCM1796 incorporates noise suppression using the system clock (SCK). However, there must be no more than two noise spikes in 600 ns. The noise suppression works for SCK frequencies between 8 MHz and 40 MHz in fast mode. However, it works incorrectly in the following conditions. Case 1: 1. t(SCK) > 120 ns (t(SCK): period of SCK) 2. t(HI) + t(D–HD) < t(SCK) × 5 3. Spike noise exists on the first half of the SCL HIGH pulse. 4. Spike noise exists on the SDA HIGH pulse just before SDA goes LOW. SCL Noise SDA When these conditions occur at the same time, the data is recognized as LOW. Case 2: 1. t(SCK) > 120 ns 2. t(S–HD) or t(RS–HD) < t(SCK) × 5 3. Spike noise exists on both SCL and SDA during the hold time. SCL Noise SDA When these conditions occur at the same time, the PCM1796 fails to detect a start condition. Case 3: 1. t(SCK) < 50 ns 2. t(SP) > t(SCK) 3. Spike noise exists on SCL just after SCL goes LOW. 4. Spike noise exists on SDA just before SCL goes LOW. SCL SDA Noise When these conditions occur at the same time, the PCM1796 erroneously detects a start or stop condition. 23 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 TIMING DIAGRAM Start Repeated Start Stop t(D-HD) t(BUF) t(D-SU) t(SDA-F) t(P-SU) t(SDA-R) SDA t(SCL-R) t(RS-HD) t(SP) t(LOW) SCL t(S-HD) t(HI) t(RS-SU) t(SCL-F) TIMING CHARACTERISTICS PARAMETER f(SCL) SCL clock frequency t(BUF) Bus free time between stop and start conditions t(LOW) Low period of the SCL clock t(HI) High period of the SCL clock t(RS-SU) t(S-HD) t(RS-HD) Hold time for (repeated) start condition Data setup time t(D-HD) Data hold time t(SCL-R) Rise time of SCL signal Rise time of SCL signal after a repeated start condition and after an t(SCL-R1) acknowledge bit t(SCL-F) Fall time of SCL signal t(SDA-R) Rise time of SDA signal t(SDA-F) Fall time of SDA signal t(P-SU) Setup time for stop condition C(B) t(SP) Capacitive load for SDA and SCL line VNH Noise margin at high level for each connected device (including hysteresis) 400 Standard 4.7 Fast 1.3 Standard 4.7 Fast 1.3 UNIT kHz µs µs µs 4 Fast 600 ns Standard 4.7 µs Fast 600 ns 4 µs Fast 600 ns Standard 250 Fast 100 Standard ns Standard 0 900 Fast 0 900 Standard 20 + 0.1 CB 1000 Fast 20 + 0.1 CB 300 Standard 20 + 0.1 CB 1000 Fast 20 + 0.1 CB 300 Standard 20 + 0.1 CB 1000 Fast 20 + 0.1 CB 300 Standard 20 + 0.1 CB 1000 Fast 20 + 0.1 CB 300 Standard 20 + 0.1 CB 1000 Fast 20 + 0.1 CB 300 Fast 0.2 VDD ns ns ns ns ns ns µs 4 600 Fast Figure 34. Timing Definition on the I2C Bus 24 MAX Fast Standard Pulse duration of suppressed spike MIN 100 Standard Setup time for (repeated) start condition t(D-SU) CONDITIONS Standard ns 400 pF 50 ns V 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 MODE CONTROL REGISTERS User-Programmable Mode Controls The PCM1796 includes a number of user-programmable functions which are accessed via mode control registers. The registers are programmed using the serial control interface, which is previously discussed in the SPI Interface and I2C INTERFACE sections of this data sheet. Table 3 lists the available mode-control functions, along with their default reset conditions and associated register index. Table 3. User-Programmable Function Controls FUNCTION DEFAULT REGISTER BIT PCM DSD DF BYPASS Digital attenuation control 0 dB to –120 dB and mute, 0.5 dB step 0 dB Register 16 Register 17 ATL[7:0] (for L-ch) ATR[7:0] (for R-ch) yes Attenuation load control Disabled, enabled Attenuation disabled Register 18 ATLD yes Input audio data format selection 16-, 20-, 24-bit standard (right-justified) format 24-bit MSB-first left-justified format 16-/24-bit I2S format 24-bit I2S format Register 18 FMT[2:0] yes Sampling rate selection for de-emphasis Disabled,44.1 kHz, 48 kHz, 32 kHz De-emphasis disabled Register 18 DMF[1:0] yes De-emphasis control Disabled, enabled De-emphasis disabled Register 18 DME yes Soft mute control Soft mute disabled, enabled Mute disabled Register 18 MUTE yes Output phase reversal Normal, reverse Normal Register 19 REV yes Attenuation speed selection ×1fS, ×(1/2)fS, ×(1/4)fS, ×(1/8)fS DAC operation control Enabled, disabled ×1 fS Register 19 ATS[1:0] yes DAC operation enabled Register 19 OPE yes Stereo DF bypass mode select Monaural, stereo Monaural Register 19 DFMS Digital filter rolloff selection Sharp rolloff, slow rolloff Sharp rolloff Register 19 FLT yes Infinite zero mute control Disabled, enabled Disabled Register 19 INZD yes System reset control Reset operation , normal operation Normal operation Register 20 SRST yes yes DSD interface mode control DSD enabled, disabled Disabled Register 20 DSD yes yes Digital-filter bypass control DF enabled, DF bypass DF enabled Register 20 DFTH yes Monaural mode selection Stereo, monaural Stereo Register 20 MONO yes yes yes Channel selection for monaural mode data L-channel, R-channel L-channel Register 20 CHSL yes yes yes Delta-sigma oversampling rate selection ×64 fS, ×128 fS, ×32 fS ×64 fS Register 20 OS[1:0] yes yes(2) yes PCM zero output enable Enabled Register 21 PCMZ yes DSD zero output enable Disabled Register 21 DZ[1:0] Not zero = 0 Zero detected = 1 Register 22 ZFGL (for L-ch) ZFGR (for R-ch) yes yes(1) yes yes yes yes yes yes yes yes yes yes FUNCTION AVAILABLE ONLY FOR READ Zero detection flag Not zero, zero detected Device ID (at TDMCA) – Register 23 ID[4:0] (1) When in DSD mode, DMF[1:0] is defined as DSD filter (analog FIR) performance selection. (2) When in DSD mode, OS[1:0] is defined as DSD filter (analog FIR) operation rate selection. yes yes yes yes 25 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Register Map The mode control register map is shown in Table 4. Registers 16–21 include an R/W bit, which determines whether a register read (R/W = 1) or write (R/W = 0) operation is performed. Registers 22 and 23 are read-only. Table 4. Mode Control Register Map B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Register 16 R/W 0 0 1 0 0 0 0 ATL7 ATL6 ATL5 ATL4 ATL3 ATL2 ATL1 ATL0 Register 17 R/W 0 0 1 0 0 0 1 ATR7 ATR6 ATR5 ATR4 ATR3 ATR2 ATR1 ATR0 Register 18 R/W 0 0 1 0 0 1 0 ATLD FMT2 FMT1 FMT0 DMF1 DMF0 DME MUTE Register 19 R/W 0 0 1 0 0 1 1 REV ATS1 ATS0 OPE RSV DFMS FLT INZD Register 20 R/W 0 0 1 0 1 0 0 RSV SRST DSD DFTH MONO CHSL OS1 OS0 Register 21 R/W 0 0 1 0 1 0 1 RSV RSV RSV RSV RSV DZ1 DZ0 PCMZ Register 22 R 0 0 1 0 1 1 0 RSV RSV RSV RSV RSV RSV ZFGR ZFGL Register 23 R 0 0 1 0 1 1 1 RSV RSV RSV ID4 ID3 ID2 ID1 ID0 Register Definitions B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Register 16 R/W 0 0 1 0 0 0 0 ATL7 ATL6 ATL5 ATL4 ATL3 ATL2 ATL1 ATL0 Register 17 R/W 0 0 1 0 0 0 1 ATR7 ATR6 ATR5 ATR4 ATR3 ATR2 ATR1 ATR0 R/W: Read/Write Mode Select When R/W = 0, a write operation is performed. When R/W = 1, a read operation is performed. Default value: 0 ATx[7:0]: Digital Attenuation Level Setting These bits are available for read and write. Default value: 1111 1111b Each DAC output has a digital attenuator associated with it. The attenuator can be set from 0 dB to –120 dB, in 0.5-dB steps. Alternatively, the attenuator can be set to infinite attenuation (or mute). The attenuation data for each channel can be set individually. However, the data load control (the ATLD bit of control register 18) is common to both attenuators. ATLD must be set to 1 in order to change an attenuator setting. The attenuation level can be set using the following formula: Attenuation level (dB) = 0.5 dB • (ATx[7:0] DEC – 255) where ATx[7:0] DEC = 0 through 255 For ATx[7:0] DEC = 0 through 14, the attenuator is set to infinite attenuation. The following table shows attenuation levels for various settings: 26 ATx[7:0] Decimal Value Attenuation Level Setting 1111 1111b 255 0 dB, no attenuation (default) 1111 1110b 254 –0.5 dB 1111 1101b 253 –1.0 dB L L 0001 0000b 16 –119.5 dB 0000 1111b 15 –120.0 dB 0000 1110b 14 Mute L L L 0000 0000b 0 Mute L 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Register 18 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 R/W 0 0 1 0 0 1 0 ATLD FMT2 FMT1 FMT0 B3 B2 DMF1 DMF0 B1 B0 DME MUTE R/W: Read/Write Mode Select When R/W = 0, a write operation is performed. When R/W = 1, a read operation is performed. Default value: 0 ATLD: Attenuation Load Control This bit is available for read and write. Default value: 0 ATLD = 0 Attenuation control disabled (default) ATLD = 1 Attenuation control enabled The ATLD bit is used to enable loading of the attenuation data contained in registers 16 and 17. When ATLD = 0, the attenuation settings remain at the previously programmed levels, ignoring new data loaded from registers 16 and 17. When ATLD = 1, attenuation data written to registers 16 and 17 is loaded normally. FMT[2:0]: Audio Interface Data Format These bits are available for read and write. Default value: 101 FMT[2:0] Audio Data Format Selection 000 16-bit standard format, right-justified data 001 20-bit standard format, right-justified data 010 24-bit standard format, right-justified data 011 24-bit MSB-first, left-justified format data 100 16-bit I2S format data 101 24-bit I2S format data (default) 110 Reserved 111 Reserved The FMT[2:0] bits are used to select the data format for the serial audio interface. For the external digital filter interface mode (DFTH mode), this register is operated as shown in the APPLICATION FOR EXTERNAL DIGITAL FILTER INTERFACE section of this data sheet. DMF[1:0]: Sampling Frequency Selection for the De-Emphasis Function These bits are available for read and write. Default value: 00 DMF[1:0] De-Emphasis Sampling Frequency Selection 00 Disabled (default) 01 48 kHz 10 44.1 kHz 11 32 kHz The DMF[1:0] bits are used to select the sampling frequency used by the digital de-emphasis function when it is enabled by setting the DME bit. The de-emphasis curves are shown in the TYPICAL PERFORMANCE CURVES section of this data sheet. For the DSD mode, analog FIR filter performance can be selected using this register. A register map and filter response plots are shown in the APPLICATION FOR DSD FORMAT (DSD MODE) INTERFACE section of this data sheet. 27 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 DME: Digital De-Emphasis Control This bit is available for read and write. Default value: 0 DME = 0 De-emphasis disabled (default) DME = 1 De-emphasis enabled The DME bit is used to enable or disable the de-emphasis function for both channels. MUTE: Soft Mute Control This bit is available for read and write. Default value: 0 MUTE = 0 Soft mute disabled (default) MUTE = 1 Soft mute enabled The MUTE bit is used to enable or disable the soft mute function for both channels. Soft mute is operated as a 256-step attenuator. The speed for each step to –∞ dB (mute) is determined by the attenuation rate selected in the ATS register. Register 19 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 R/W 0 0 1 0 0 1 1 REV ATS1 ATS0 OPE RSV DFMS FLT INZD R/W: Read/Write Mode Select When R/W = 0, a write operation is performed. When R/W = 1, a read operation is performed. Default value: 0 REV: Output Phase Reversal This bit is available for read and write. Default value: 0 REV = 0 Normal output (default) REV = 1 Inverted output The REV bit is used to invert the output phase for both channels. ATS[1:0]: Attenuation Rate Select These bits are available for read and write. Default value: 00 ATS[1:0] Attenuation Rate Selection 00 Every LRCK (default) 01 LRCK/2 10 LRCK/4 11 LRCK/8 The ATS[1:0] bits are used to select the rate at which the attenuator is decremented/incremented during level transitions. 28 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 OPE: DAC Operation Control This bit is available for read and write. Default value: 0 OPE = 0 DAC operation enabled (default) OPE = 1 DAC operation disabled The OPE bit is used to enable or disable the analog output for both channels. Disabling the analog outputs forces them to the bipolar zero level (BPZ) even if audio data is present on the input. DFMS: Stereo DF Bypass Mode Select This bit is available for read and write. Default value: 0 DFMS = 0 Monaural (default) DFMS = 1 Stereo input enabled The DFMS bit is used to enable stereo operation in DF bypass mode. In the DF bypass mode, when DFMS is set to 0, the pin for the input data is DATA (pin 5) only, therefore the PCM1796 operates as a monaural DAC. When DFMS is set to 1, the PCM1796 can operate as a stereo DAC with inputs of L-channel and R-channel data on ZEROL (pin 1) and ZEROR (pin 2), respectively. FLT: Digital Filter Rolloff Control This bit is available for read and write. Default value: 0 FLT = 0 Sharp rolloff (default) FLT = 1 Slow rolloff The FLT bit is used to select the digital filter rolloff characteristic. The filter responses for these selections are shown in the TYPICAL PERFORMANCE CURVES section of this data sheet. INZD: Infinite Zero Detect Mute Control This bit is available for read and write. Default value: 0 INZD = 0 Infinite zero detect mute disabled (default) INZD = 1 Infinite zero detect mute enabled The INZD bit is used to enable or disable the zero detect mute function. Setting INZD to 1 forces muted analog outputs to hold a bipolar zero level when the PCM1796 detects a zero condition in both channels. The infinite zero detect mute function is not available in the DSD mode. Register 20 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 R/W 0 0 1 0 1 0 0 RSV SRST DSD DFTH MONO CHSL OS1 OS0 R/W: Read/Write Mode Select When R/W = 0, a write operation is performed. When R/W = 1, a read operation is performed. Default value: 0 29 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 SRST: System Reset Control This bit is available for write only. Default value: 0 SRST = 0 Normal operation (default) SRST = 1 System reset operation (generate one reset pulse) The SRST bit is used to reset the PCM1796 to the initial system condition. DSD: DSD Interface Mode Control This bit is available for read and write. Default value: 0 DSD = 0 DSD interface mode disabled (default) DSD = 1 DSD interface mode enabled The DSD bit is used to enable or disable the DSD interface mode. DFTH: Digital Filter Bypass (or Through Mode) Control This bit is available for read and write. Default value: 0 DFTH = 0 Digital filter enabled (default) DFTH = 1 Digital filter bypassed for external digital filter The DFTH bit is used to enable or disable the external digital filter interface mode. MONO: Monaural Mode Selection This bit is available for read and write. Default value: 0 MONO = 0 Stereo mode (default) MONO = 1 Monaural mode The MONO function is used to change operation mode from the normal stereo mode to the monaural mode. When the monaural mode is selected, both DACs operate in a balanced mode for one channel of audio input data. Channel selection is available for L-channel or R-channel data, determined by the CHSL bit as described immediately following. CHSL: Channel Selection for Monaural Mode This bit is available for read and write. Default value: 0 CHSL = 0 L-channel selected (default) CHSL = 1 R-channel selected This bit is available when MONO = 1. The CHSL bit selects L-channel or R-channel data to be used in monaural mode. 30 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 OS[1:0]: Delta-Sigma Oversampling Rate Selection These bits are available for read and write. Default value: 00 Operation Speed Select OS[1:0] 00 64 times fS (default) 01 32 times fS 10 128 times fS 11 Reserved The OS bits are used to change the oversampling rate of delta-sigma modulation. Use of this function enables the designer to stabilize the conditions at the post low-pass filter for different sampling rates. As an application example, programming to set 128 times in 44.1-kHz operation, 64 times in 96-kHz operation, and 32 times in 192-kHz operation allows the use of only a single type (cutoff frequency) of post low-pass filter. The 128 fS oversampling rate is not available at sampling rates above 100 kHz. If the 128-fS oversampling rate is selected, a system clock of more than 256 fS is required. In DSD mode, these bits are used to select the speed of the bit clock for DSD data coming into the analog FIR filter. Register 21 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 R/W 0 0 1 0 1 0 1 RSV RSV RSV RSV RSV DZ1 DZ0 PCMZ R/W: Read/Write Mode Select When R/W = 0, a write operation is performed. When R/W = 1, a read operation is performed. Default value: 0 DZ[1:0]: DSD Zero Output Enable These bits are available for read and write. Default value: 00 Zero Output Enable DZ[1:0] 00 Disabled (default) 01 Even pattern detect 1x 96h pattern detect The DZ bits are used to enable or disable the output zero flags, and to select the zero pattern in the DSD mode. PCMZ: PCM Zero Output Enable These bits are available for read and write. Default value: 1 PCMZ = 0 PCM zero output disabled PCMZ = 1 PCM zero output enabled (default) The PCMZ bit is used to enable or disable the output zero flags in the PCM mode and the external DF mode. Register 22 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 R 0 0 1 0 1 1 0 RSV RSV RSV RSV RSV RSV ZFGR ZFGL R: Read Mode Select Value is always 1, specifying the readback mode. 31 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ZFGx: Zero-Detection Flag Where x = L or R, corresponding to the DAC output channel. These bits are available only for readback. Default value: 00 ZFGx = 0 Not zero ZFGx = 1 Zero detected These bits show zero conditions. Their status is the same as that of the zero flags at ZEROL (pin 1) and ZEROR (pin 2). See Zero Detect in the FUNCTION DESCRIPTIONS section. Register 23 B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 R 0 0 1 0 1 1 1 RSV RSV RSV ID4 ID3 ID2 ID1 ID0 R: Read Mode Select Value is always 1, specifying the readback mode. ID[4:0]: Device ID The ID[4:0] bits hold a device ID in the TDMCA mode. 32 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 APPLICATION INFORMATION TYPICAL CONNECTION DIAGRAM IN PCM MODE Cf 5V Rf 1 ZEROL VCC2L 28 2 ZEROR AGND3L 27 3 MSEL IOUTL– 26 4 LRCK IOUTL+ 25 5 DATA AGND2 24 6 BCK VCC1 23 VCOML 22 VCOMR 21 IREF 20 10 MS AGND1 19 11 MDI IOUTR– 18 12 MC IOUTR+ 17 AGND3R 16 VCC2R 15 + 0.1 µF 10 µF – 7 0.1 µF Controller SCK 8 DGND 9 VDD 13 MDO Rf 5V – 10 µF + Differential to Single Converter With Low-Pass Filter VOUT L-Channel Differential to Single Converter With Low-Pass Filter VOUT R-Channel + Cf 47 µF Rf 10 kΩ – + Cf 0.1 µF Rf 5V + 14 RST PCM1796 Cf + PCM Audio Data Source + 10 µF – + 3.3 V + 10 µF Figure 35. Typical Application Circuit for Standard PCM Audio Operation APPLICATION CIRCUIT The design of the application circuit is very important in order to actually realize the high S/N ratio of which the PCM1796 is capable. This is because noise and distortion that are generated in an application circuit are not negligible. In the third-order LPF circuit of Figure 36, the output level is 2.1 V rms and 123 dB S/N is achieved. Figure 37 shows a circuit for the DSD mode, which is a fourth-order LPF in order to reduce the out-of-band noise. I/V Section The current of the PCM1796 on each of the output pins (IOUTL+, IOUTL–, IOUTR+, IOUTR–) is 4 mA p-p at 0 dB (full scale). The voltage output level of the I/V converter (Vi) is given by following equation: Vi = 4 mA p-p × Rf (Rf : feedback resistance of I/V converter) An NE5534 operational amplifier is recommended for the I/V circuit to obtain the specified performance. Dynamic performance such as the gain bandwidth, settling time, and slew rate of the operational amplifier affects the audio dynamic performance of the I/V section. 33 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Differential Section The PCM1796 voltage outputs are followed by differential amplifier stages, which sum the differential signals for each channel, creating a single-ended I/V op-amp output. In addition, the differential amplifiers provide a low-pass filter function. The operational amplifier recommended for the differential circuit is the low-noise type. C1 2700 pF R1 820 Ω VCC VCC C11 0.1 µF C17 22 pF 7 IOUT– 5 2 8 – 3 R5 200 Ω 6 + U1 NE5534 4 R3 220 Ω C3 8200 pF R7 180 Ω C5 27000 pF C15 0.1 µF C19 22 pF 7 2 3 5 – 6 + 4 C12 0.1 µF VEE R4 220 Ω R6 200 Ω 8 R8 180 Ω R9 100 Ω U3 NE5534 C16 0.1 µF C4 8200 pF VEE C2 2700 pF R2 820 Ω VCC C13 0.1 µF C18 22 pF 7 IOUT+ 2 3 5 – 8 6 + 4 U2 NE5534 VCC = 15 V VEE = –15 V fc = 50 kHz C14 0.1 µF VEE Figure 36. Measurement Circuit for PCM 34 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 C1 2200 pF R1 820 Ω VCC VCC C11 0.1 µF C17 22 pF 7 IOUT– 5 2 8 – 3 R5 150 Ω 6 + R3 91 Ω R10 120 Ω C3 22000 pF U1 NE5534 4 R8 75 Ω C5 8200 pF C4 27000 pF C15 0.1 µF C19 22 pF 7 2 3 5 – 6 + 4 C12 0.1 µF VEE R4 91 Ω R9 75 Ω R6 150 Ω 8 R11 120 Ω R7 100 Ω U3 NE5534 C16 0.1 µF C6 8200 pF VEE C2 2200 pF R2 820 Ω VCC C13 0.1 µF C18 22 pF 7 IOUT+ 2 3 5 – 8 6 + 4 U2 NE5534 VCC = 15 V VEE = –15 V fc = 50 kHz C14 0.1 µF VEE Figure 37. Measurement Circuit for DSD 35 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 IOUTL– (Pin 26) IOUT– IOUTL+ (Pin 25) IOUT+ Figure 36 Circuit OUT+ 3 1 2 IOUTR– (Pin 18) IOUT– Figure 36 Circuit IOUTR+ (Pin 17) IOUT+ OUT– Balanced Out Figure 38. Measurement Circuit for Monaural Mode 36 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 APPLICATION FOR EXTERNAL DIGITAL FILTER INTERFACE DFMS = 0 External Filter Device PCM1796 1 ZEROL 2 ZEROR 3 MSEL WDCK (Word Clock) 4 LRCK DATA 5 DATA BCK 6 BCK SCK 7 SCK DFMS = 1 External Filter Device PCM1796 DATA_L 1 ZEROL DATA_R 2 ZEROR 3 MSEL 4 LRCK 5 DATA BCK 6 BCK SCK 7 SCK WDCK (Word Clock) Figure 39. Connection Diagram for External DIgital Filter (Internal DF Bypass Mode) Application 37 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Application for Interfacing With an External Digital Filter For some applications, it may be desirable to use an external digital filter to perform the interpolation function, as it can provide improved stop-band attenuation when compared to the internal digital filter of the PCM1796. The PCM1796 supports several external digital filters, including: D Texas Instruments DF1704 and DF1706 D Pacific Microsonics PMD200 HDCD filter/decoder IC D Programmable digital signal processors The external digital filter application mode is accessed by programming the following bits in the corresponding control register: D DFTH = 1 (register 20) The pins used to provide the serial interface for the external digital filter are shown in the connection diagram of Figure 39. The word clock (WDCK) signal must be operated at 8× or 4× the desired sampling frequency, fS. Pin Assignment When Using the External Digital Filter Interface D D D D D 38 LRCK (pin 4): WDCK as word clock input BCK (pin 6): Bit clock for audio data DATA (pin 5): Monaural audio data input when the DFMS bit is not set to 1 ZEROL (pin 1): DATAL as L-channel audio data input when the DFMS bit is set to 1 ZEROR (pin 2): DATAR as R-channel audio data input when the DFMS bit is set to 1 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Audio Format The PCM1796 in the external digital filter interface mode supports right-justified audio formats including 16-bit, 20-bit, and 24-bit audio data, as shown in Figure 40. The audio format is selected by the FMT[2:0] bits of control register18. 1/4 fS or 1/8 fS WDCK BCK Audio Data Word = 16-Bit DATA, DATAL, DATAR 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 MSB LSB Audio Data Word = 20-Bit DATA, DATAL, DATAR 19 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 MSB LSB Audio Data Word = 24-Bit DATA, DATAL, DATAR 23 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 MSB LSB Figure 40. Audio Data Input Format for External Digital Filter (Internal DF Bypass Mode) Application System Clock (SCK) and Interface Timing The PCM1796 in an application using an external digital filter requires the synchronization of WDCK and the system clock. The system clock is phase-free with respect to WDCK. Interface timing among WDCK, BCK, DATA, DATAL, and DATAR is shown in Figure 41. 1.4 V WDCK t(BCH) t(BCL) t(LB) 1.4 V BCK t(BCY) t(BL) DATA DATAL DATAR 1.4 V t(DS) t(DH) PARAMETER t(BCY) BCK pulse cycle time t(BCL) BCK pulse duration, LOW MIN MAX UNITS 20 ns 7 ns t(BCH) BCK pulse duration, HIGH t(BL) BCK rising edge to WDCK falling edge 7 ns 5 ns t(LB) t(DS) WDCK falling edge to BCK rising edge 5 ns DATA, DATAL, DATAR setup time 5 ns t(DH) DATA, DATAL, DATAR hold time 5 ns Figure 41. Audio Interface Timing for External Digital Filter (Internal DF Bypass Mode) Application 39 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 FUNCTIONS AVAILABLE IN THE EXTERNAL DIGITAL FILTER MODE The external digital filter mode is selected by setting DSD = 0 (register 20, B5) and DFTH = 1 (register 20. B4). The external digital filter mode allows access to the majority of the PCM1796 mode control functions. The following table shows the register mapping available when the external digital filter mode is selected, along with descriptions of functions which are modified when using this mode selection. B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Register 16 R/W 0 0 1 0 0 0 0 – – – – – – – – Register 17 R/W 0 0 1 0 0 0 1 – – – – – – – – Register 18 R/W 0 0 1 0 0 1 0 – FMT2 FMT1 FMT0 – – – – Register 19 R/W 0 0 1 0 0 1 1 REV – – OPE – DFMS – INZD Register 20 R/W 0 0 1 0 1 0 0 – SRST 0 1 MONO CHSL OS1 OS0 Register 21 R/W 0 0 1 0 1 0 1 – – – – – – – PCMZ Register 22 R 0 0 1 0 1 1 0 – – – – – – ZFGR ZFGL NOTE: –: Function is disabled. No operation even if data bit is set FMT[2:0]: Audio Data Format Selection Default value: 000 FMT[2:0] Audio Data Format Select 000 16-bit right-justified format (default) 001 20-bit right-justified format 010 24-bit right-justified format Other N/A OS[1:0]: Delta-Sigma Modulator Oversampling Rate Selection Default value: 00 OS[1:0] Operation Speed Select 00 8 times WDCK (default) 01 4 times WDCK 10 16 times WDCK 11 Reserved The effective oversampling rate is determined by the oversampling performed by both the external digital filter and the delta-sigma modulator. For example, if the external digital filter is 8× oversampling, and the user selects OS[1:0] = 00, then the delta-sigma modulator oversamples by 8×, resulting in an effective oversampling rate of 64×. The 16× WDCK oversampling rate is not available above a 100-kHz sampling rate. If the oversampling rate selected is 16× WDCK, the system clock frequency must be over 256 fS. 40 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 APPLICATION FOR DSD FORMAT (DSD MODE) INTERFACE DSD Decoder PCM1796 1 ZEROL 2 ZEROR 3 MSEL DATA_R 4 LRCK DATA_L 5 DATA 6 BCK 7 SCK Bit Clock Figure 42. Connection Diagram in DSD Mode Feature This mode is used for interfacing directly to a DSD decoder, which is found in Super Audio CDt (SACD) applications. The DSD mode is accessed by programming the following bit in the corresponding control register. DSD = 1 (register 20) The DSD mode provides a low-pass filtering function. The filtering is provided using an analog FIR filter structure. Four FIR responses are available, and are selected by the DMF[1:0] bits of control register 18. The DSD bit must be set before inputting DSD data; otherwise, the PCM1796 erroneously detects the TDMCA mode, and commands are not accepted through the serial control interface. Pin Assignment When Using DSD Format Interface Several pins are redefined for DSD mode operation. These include: D D D D DATA (pin 5): DSDL as L-channel DSD data input LRCK (pin 4): DSDR as R-channel DSD data input SCK (pin 7): DBCK as bit clock for DSD data BCK (pin 6): Set LOW (N/A) Super Audio CD is a trademark of Sony Kabushiki Kaisha TA Sony Corporation, Japan. 41 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Requirements for System Clock For operation in the DSD mode, the bit clock (DBCK) is required on pin 7 of the PCM1796. The frequency of the bit clock can be N times the sampling frequency. Generally, N is 64 in DSD applications. The interface timing between the bit clock and DSDL and DSDR is required to meet the setup and hold time specifications shown in Figure 44. t = 1/(64 × 44.1 kHz) DBCK DSDL DSDR D0 D1 D2 D3 D4 Figure 43. Normal Data Output Form From DSD Decoder t(BCH) t(BCL) 1.4 V DBCK t(BCY) DSDL DSDR 1.4 V t(DS) t(DH) PARAMETER t(BCY) DBCK pulse cycle time t(BCH) DBCK high-level time t(BCL) DBCK low-level time t(DS) DSDL, DSDR setup time MIN 85(1) MAX UNITS ns 30 ns 30 ns 10 ns t(DH) DSDL, DSDR hold time 10 ns (1) 2.8224 MHz × 4. (2.8224 MHz = 64 × 44.1 kHz. This value is specified as a sampling rate of DSD.) Figure 44. Timing for DSD Audio Interface 42 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ANALOG FIR FILTER PERFORMANCE IN DSD MODE GAIN vs FREQUENCY GAIN vs FREQUENCY 0 0 −1 −10 −2 −20 Gain – dB Gain – dB fc = 185 kHz Gain(1) = –6.6 dB −3 −30 −4 −40 −5 −50 −6 −60 0 50 100 150 200 0 500 f – Frequency – kHz 1000 1500 f – Frequency – kHz Figure 45. DSD Filter-1, Low BW Figure 46. DSD Filter-1, High BW GAIN vs FREQUENCY GAIN vs FREQUENCY 0 0 −1 −10 −2 −20 Gain – dB Gain – dB fc = 90 kHz Gain(1) = 0.3 dB −3 −30 −4 −40 −5 −50 −6 −60 0 50 100 150 200 0 500 f – Frequency – kHz Figure 47. DSD Filter-2, Low BW 1000 1500 f – Frequency – kHz Figure 48. DSD Filter-2, High BW (1) This gain is in comparison to PCM 0 dB, when the DSD input signal efficiency is 50%. All specifications at DBCK = 2.8224 MHz (44.1 kHz × 64 fS), and 50% modulation DSD data input, unless otherwise noted. 43 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ANALOG FIR FILTER PERFORMANCE IN DSD MODE (CONTINUED) GAIN vs FREQUENCY GAIN vs FREQUENCY 0 0 −1 −10 −2 −20 Gain – dB Gain – dB fc = 85 kHz Gain(1) = –1.5 dB −3 −30 −4 −40 −5 −50 −6 −60 0 50 100 150 200 0 f – Frequency – kHz 500 1000 1500 f – Frequency – kHz Figure 49. DSD Filter-3, Low BW Figure 50. DSD Filter-3, High BW GAIN vs FREQUENCY GAIN vs FREQUENCY 0 0 −1 −10 −2 −20 Gain – dB Gain – dB fc = 94 kHz Gain(1) = –3.3 dB −3 −30 −4 −40 −5 −50 −6 −60 0 50 100 150 200 0 f – Frequency – kHz Figure 51. DSD Filter-4, Low BW 500 1000 f – Frequency – kHz Figure 52. DSD Filter-4, High BW (1) This gain is in comparison to PCM 0 dB, when the DSD input signal efficiency is 50%. All specifications at DBCK = 2.8224 MHz (44.1 kHz × 64 fS), and 50% modulation DSD data input, unless otherwise noted. 44 1500 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 DSD MODE CONFIGURATION AND FUNCTION CONTROLS Configuration for the DSD Interface Mode The DSD interface mode is selected by setting DSD = 1 (register 20, B5). B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Register 16 R/W 0 0 1 0 0 0 0 – – – – – – – – Register 17 R/W 0 0 1 0 0 0 1 – – – – – – – – Register 18 R/W 0 0 1 0 0 1 0 – – – – DMF1 DMF0 – – Register 19 R/W 0 0 1 0 0 1 1 REV – – OPE – – – – Register 20 R/W 0 0 1 0 1 0 0 – SRST 1 – MONO CHSL OS1 OS0 Register 21 R 0 0 1 0 1 0 1 – – – – – DZ1 DZ0 – Register 22 R 0 0 1 0 1 1 0 – – – – – – ZFGR ZFGL NOTE: –: Function is disabled. No operation even if data bit is set DMF[1:0]: Analog-FIR Performance Selection Default value: 00 DMF[1:0] Analog-FIR Performance Select 00 FIR-1 (default) 01 FIR-2 10 FIR-3 11 FIR-4 Plots for the four analog FIR filter responses are shown in the ANALOG FIR FILTER PERFORMANCE IN DSD MODE section of this data sheet. OS[1:0]: Analog-FIR Operation-Speed Selection Default value: 00 OS[1:0] Operation-Speed Select 00 fDBCK (default) 01 fDBCK /2 10 Reserved 11 fDBCK/4 The OS bit in the DSD mode is used to select the operating rate of the analog FIR. The OS bits must be set before setting the DSD bit to1. 45 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 TDMCA INTERFACE FORMAT The PCM1796 supports the time-division-multiplexed command and audio (TDMCA) data format to simplify the host control serial interface. The TDMCA format is designed not only for the McBSP of TI DSPs but also for any programmable devices. The TDMCA format can transfer not only audio data but also command data, so that it can be used together with any kind of device that supports the TDMCA format. The TDMCA frame consists of a command field, extended command field, and some audio data fields. Those audio data are transported to IN devices (such as a DAC) and/or from OUT devices (such as an ADC). The PCM1796 is an IN device. LRCK and BCK are used with both IN and OUT devices so that the sample frequency of all devices in a system must be the same. The TDMCA mode supports a maximum of 30 device IDs. The maximum number of audio channels depends on the BCK frequency. TDMCA Mode Determination The PCM1796 recognizes the TDMCA mode automatically when it receives an LRCK signal with a pulse duration of two BCK clocks. If the TDMCA mode operation is not needed, the duty cycle of LRCK must be 50%. Figure 53 shows the LRCK and BCK timing that determines the TDMCA mode. The PCM1796 enters the TDMCA mode after two continuous TDMCA frames. Any TDMCA commands can be issued during the next TDMCA frame after the TDMCA mode is entered. Pre-TDMCA Frame TDMCA Frame Command Accept LRCK 2 BCKs BCK Figure 53. LRCK and BCK Timing for Determination of TDMCA Mode TDMCA Terminals TDMCA requires six signals, of which four signals are for command and audio data interface, and one pair for daisy chaining. Those signals can be shared as in the following table. The DO signal has a 3-state output so that it can be connected directly to other devices. TERMINAL NAME TDMCA NAME PROPERTY LRCK LRCK input TDMCA frame start signal. It must be the same as the sampling frequency. BCK BCK input TDMCA clock. Its frequency must be high enough to communicate a TDMCA frame within an LRCK cycle. TDMCA command and audio data input signal 46 DATA DI input MDO DO output DESCRIPTION TDMCA command data 3-state output signal MC DCI input TDMCA daisy-chain input signal MS DCO output TDMCA daisy-chain output signal 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Device ID Determination The TDMCA mode also supports a multichip implementation in one system. This means a host controller (DSP) can simultaneously support several TDMCA devices, which can be of the same type or different types, including PCM devices. The PCM devices are categorized as IN device, OUT device, IN/OUT device, and NO device. The IN device has an input port to receive audio data, the OUT device has an output port to supply audio data, the IN/OUT device has both input and output ports for audio data, and the NO device has no port for audio data but needs command data from the host. A DAC is an IN device, an ADC is an OUT device, a codec is an IN/OUT device, and a PLL is a NO device. The PCM1796 is an IN device. For the host controller to distinguish the devices, each device is assigned its own device ID by the daisy chain. The devices obtain their own device IDs automatically by connecting their DCI to the DCO of the preceding device and their DCO to the DCI of the following device in the daisy chain. The daisy chains are categorized as the IN chain and the OUT chain, which are completely independent and equivalent. Figure 54 shows an example daisy chain connection. If a system needs to chain the PCM1796 and a NO device in the same IN or OUT chain, the NO device must be chained at the back end of the chain because it does not require any audio data. Figure 55 shows an example of TDMCA system including an IN chain and an OUT chain with a TI DSP. For a device to get its own device ID, the DID signal must be set to 1 (see the Command Field section for details), and LRCK and BCK must be driven in the TDMCA mode for all PCM devices that are chained. The device at the top of the chain knows its device ID is 1 because its DCI is fixed HIGH. Other devices count the BCK pulses and observe their own DCI signal to determine their position and ID. Figure 56 shows the initialization of each device ID. IN DCO DCI DCO DCI NO Device NO Device DCO ••• DCI DCO DCIo OUT DCOo NO Device IN/OUT Device OUT DCIo DCO DCI DCO DCI ••• ••• ••• NO Device DCI IN/OUT Device OUT Device DCOi IN DCOo IN Device OUT Device DCIi DCOi DCIi ••• IN Device DCO DCI DCO DCI IN Chain OUT Chain Figure 54. Daisy Chain Connection 47 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 DCII LRCK BCK IN/OUT Device (DIX1700) DCOI DI DCIO DO DCOO Device ID = 1 LRCK BCK IN Device (PCM1796) DI DO LRCK DCI DCO Device ID = 2 NO Device DCI BCK DI DO DCO Device ID = 3 • • • FSX FSR CLKX CLKR DX DR LRCK OUT Device DCI BCK DI DO DCO Device ID = 2 TI DSP LRCK OUT Device DCI BCK DI DO DCO Device ID = 3 • • • Figure 55. IN Daisy Chain and OUT Daisy Chain Connection for a Multichip System 48 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 LRCK BCK DID DI Device ID = 1 DCO1 Device ID = 2 DCO1 DCI2 Command Field Device ID = 3 DCO2 DCI3 • • • • • • Device ID = 30 DCO29 DCI30 58 BCKs Figure 56. Device ID Determination Sequence TDMCA Frame In general, the TDMCA frame consists of the command field, extended command (EMD) field, and audio data fields. All of them are 32 bits in length, but the lowest byte has no meaning. The MSB is transferred first for each field. The command field is always transferred as the first packet of the frame. The EMD field is transferred if the EMD flag of the command field is HIGH. If any EMD packets are transferred, no audio data follows the EMD packets. This frame is for quick system initialization. All devices of a daisy chain should respond to the command field and extended command field. The PCM1796 has two audio channels that can be selected by OPE (register 19). If the OPE bit is not set to HIGH, those audio channels are transferred. Figure 57 shows the general TDMCA frame. If some DACs are enabled, but corresponding audio data packets are not transferred, the analog outputs are unpredictable. 1/fS LRCK BCK [For Initialization] DI CMD EMD EMD EMD EMD EMD CMD CMD CMD CMD CMD Don’t Care CMD Don’t Care CMD 32 Bits DO CMD [For Operation] DI CMD DO CMD Ch1 Ch1 Ch2 Ch3 Ch4 Ch(n) Ch2 Ch3 Ch4 Ch(m) Figure 57. General TDMCA Frame 49 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 1/fS (256 BCK Clocks) 7 Packets × 32 Bits LRCK BCK DI Ch1 CMD Ch2 Ch3 Ch4 Ch5 Ch6 Don’t Care CMD IN and OUT Channel Orders are Completely Independent DO Ch1 CMD Ch2 Figure 58. TDMCA Frame Example of 6-Ch DAC and 2-Ch ADC With Command Read Command Field The normal command field is defined as follows. When the DID bit (MSB) is 1, this frame is used only for device ID determination, and all remaining bits in the field are ignored. command 31 30 29 DID EMD DCS 28 24 device ID 23 22 R/W 16 15 register ID 8 7 data 0 not used Bit 31: Device ID enable flag The PCM1796 operates to get its own device ID for TDMCA initialization if this bit is HIGH. Bit 30: Extended command enable flag The EMD packet is transferred if this bit is HIGH, otherwise skipped. Once this bit is HIGH, this frame does not contain any audio data. This is for system initialization. Bit 29: Daisy chain selection flag HIGH designates OUT-chain devices, LOW designates IN-chain devices. The PCM1796 is an IN device, so the DCS bit must be set to LOW. Bits[28:24]: Device ID The device ID is 5 bits length, and it can be defined. These bits identify the order of a device in the IN or OUT daisy chain. The top of the daisy chain defines device ID 1 and successive devices are numbered 2, 3, 4, etc. All devices for which the DCI is fixed HIGH are also defined as ID 1. The maximum device ID is 30 each in the IN and OUT chains. If a device ID of 0x1F is used, all devices are selected as broadcast when in the write mode. If a device ID of 0x00 is used, no device is selected. Bit 23: Command Read/Write flag If this bit is HIGH, the command is a read operation. Bits[22:16]: Register ID It is 7 bits in length. Bits[15:8]: Command data It is 8 bits in length. Any valid data can be chosen for each register. Bits[7:0]: Not used These bits are never transported when a read operation is performed. Extended command field The extended command field is the same as the command field, except that it does not have a DID flag. extended command 50 31 30 29 rsvd EMD DCS 28 24 device ID 23 R/W 22 16 register ID 15 8 data 7 0 not used 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Audio Fields The audio field is 32 bits in length and the audio data is transferred MSB first, so the other fields must be stuffed with 0s as shown in the following example. audio data 31 16 MSB 24 bits 12 8 7 LSB 4 3 0 All 0s TDMCA Register Requirements TDMCA mode requires device ID and audio channel information, previously described. The OPE bit in register 19 indicates audio channel availability and register 23 indicates the device ID. Register 23 is used only in the TDMCA mode. See the mode control register map (Table 4). Register Write/Read Operation The command supports register write and read operations. If the command requests to read one register, the read data is transferred on DO during the data phase of the timing cycle. The DI signal can be retrieved at the positive edge of BCK, and the DO signal is driven at the negative edge of BCK. DO is activated one BCK cycle early to compensate for the output delay caused by high impedance. Figure 59 shows the TDMCA write and read timing. Register ID Phase Data Phase BCK DI Read Mode and Proper Register ID DO Write Data Retrieved, if Write Mode Read Data Driven, if Read Mode 1 BCK Early DOEN (Internal) Figure 59. TDMCA Write and Read Operation Timing TDMCA-Mode Operation DCO specifies the owner of the next audio channel in TDMCA-mode operation. When a device retrieves its own audio channel data, DCO goes HIGH during the last audio channel period. Figure 60 shows the DCO output timing in TDMCA-mode operation. The host controller ignores the behavior of DCI and DCO. DCO indicates the last audio channel of each device. Therefore, DCI means the next audio channel is allocated. If some devices are skipped due to no active audio channel, the skipped devices must notify the next device that the DCO will be passed through the next DCI. Figure 61 and Figure 62 show DCO timing with skip operation. Figure 63 shows the ac timing of the daisy chain signals. 51 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 1/fS (384 BCK Clocks) 9 Packets y 32 Bits LRCK BCK IN Daisy Chain CMD DI Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Don’t Care DCI1 DID = 1 DID = 2 DID = 3 DID = 4 DCO1 DCI2 DCO2 DCI3 DCO3 DCI4 DCO4 Figure 60. DCO Output Timing of TDMCA Mode Operation 1/fS (256 BCK Clocks) 5 Packets × 32 Bits LRCK BCK DI CMD Ch1 Ch2 Ch15 Ch16 Don’t Care DCI DID = 1 DCO DCI DID = 2 • • • • • • 2 BCK Delay DCO • • • 14 BCK Delay DCI DID = 8 DCO Figure 61. DCO Output Timing With Skip Operation 52 CMD CMD 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 Command Packet LRCK BCK DI DID EMD DCO1 DCO2 • • • Figure 62. DCO Output Timing With Skip Operation (for Command Packet 1) 53 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 LRCK t(LB) t(BL) BCK t(BCY) t(DS) t(DH) DI t(DOE) DO t(DS) t(DH) DCI t(COE) DCO PARAMETER t(BCY) BCK pulse cycle time t(LB) LRCK setup time MIN MAX UNITS 20 ns 0 ns t(BL) t(DS) LRCK hold time 3 ns DI setup time 0 ns t(DH) t(DS) DI hold time 3 ns DCI setup time 0 ns 3 ns t(DH) DCI hold time t(DOE) DO output delay(1) t(COE) DCO output delay(1) (1) Load capacitance is 10 pF. Figure 63. AC Timing of Daisy Chain Signals 54 8 ns 6 ns 
 www.ti.com SLES100A − DECEMBER 2003 − REVISED NOVEMBER 2006 ANALOG OUTPUT Table 5 and Figure 64 show the relationship between the digital input code and analog output. Table 5. Analog Output Current and Voltage 800000 (–FS) 000000 (BPZ) 7FFFFF (+FS) IOUTN [mA] IOUTP [mA] –1.5 –3.5 –5.5 –5.5 –3.5 –1.5 VOUTN [V] VOUTP [V] –1.23 –2.87 –4.51 –4.51 –2.87 –1.23 VOUT [V] –2.98 0 2.98 NOTE: VOUTN is the output of U1, VOUTP is the output of U2, and VOUT is the output of U3 in the measurement circuit of Figure 36. OUTPUT CURRENT vs INPUT CODE 0 IO – Output Current – mA −1 IOUTN −2 −3 −4 IOUTP −5 −6 800000(–FS) 000000(BPZ) 7FFFFF(+FS) Input Code – Hex Figure 64. The Relationship Between Digital Input and Analog Output 55 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) PCM1796DB ACTIVE SSOP DB 28 47 RoHS & Green NIPDAU Level-1-260C-UNLIM -25 to 85 PCM1796 PCM1796DBR ACTIVE SSOP DB 28 2000 RoHS & Green NIPDAU Level-1-260C-UNLIM -25 to 85 PCM1796 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of