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(/#% %$!'"($% SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 FEATURES D Dual-Supply Operation: D Supports Both DSD and PCM Formats D 24-Bit Resolution D Analog Performance: D 5-V Tolerant Digital Inputs D Small 28-Lead SSOP Package, Lead-Free − Dynamic Range: − 132 dB (9 V RMS, Mono) − 129 dB (4.5 V RMS, Stereo) − 127 dB (2 V RMS, Stereo) − THD+N: 0.0004% D Differential Current Output: 7.8 mA p-p D 8× Oversampling Digital Filter: − Stop-Band Attenuation: –130 dB − Pass-Band Ripple: ±0.00001 dB D Sampling Frequency: 10 kHz to 200 kHz D System Clock: 128, 192, 256, 384, 512, or 768 fS With Autodetect D Accepts 16-, 20-, and 24-Bit Audio Data D PCM Data Formats: Standard, I2S, and Left-Justified D Optional Interface to External Digital Filter or DSP Available D I2C-Compatible Serial Port D User-Programmable Mode Controls: − Digital Attenuation: 0 dB to –120 dB, 0.5 dB/Step − Digital De-Emphasis − Digital Filter Rolloff: Sharp or Slow − Soft Mute − 5-V Analog, 3.3-V Digital Product APPLICATIONS D A/V Receivers D SACD Player D DVD Players D HDTV Receivers D Car Audio Systems D Digital Multitrack Recorders D Other Applications Requiring 24-Bit Audio DESCRIPTION The DSD1794 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 DSD1794 provides balanced current outputs, allowing the user to optimize analog performance externally. The DSD1794 accepts the PCM and DSD audio data formats, providing easy interfacing to audio DSP and decoder chips. The DSD1794 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 I2C-compatible serial port. 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. !"#$ % &'!!($ #% )'*+&#$ ,#$(- !,'&$% &!" $ %)(&&#$% )(! $.( $(!"% (/#% %$!'"($% %$#,#!, 0#!!#$1!,'&$ )!&(%%2 ,(% $ (&(%%#!+1 &+',( $(%$2 #++ )#!#"($(!%- Copyright 2003, Texas Instruments Incorporated www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 ORDERING INFORMATION PRODUCT PACKAGE PACKAGE CODE OPERATION TEMPERATURE RANGE PACKAGE MARKING DSD1794DB 28-lead SSOP 28DB −25°C to 85°C DSD1794 ORDERING NUMBER TRANSPORT MEDIA DSD1794DB Tube DSD1794DBR Tape and reel ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range unless otherwise noted(1) DSD1794 VCC1, VCC2L, VCC2R VDD Supply voltage −0.3 V to 6.5 V −0.3 V to 4 V Supply voltage differences: VCC1, VCC2L, VCC2R ±0.1 V Ground voltage differences: AGND1, AGND2, AGND3L, AGND3R, DGND PLRCK, PDATA, PBCK, SCK, RST, SCL, SDA(2), ADR0, ADR1, DSDL(2), DSDR(2), DBCK Digital input voltage DSDL(3), DSDR(3), SDA(3) ±0.1 V Analog input 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 ±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) 250°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 (3) Output 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 DSD1794DB PARAMETER TEST CONDITIONS MIN RESOLUTION TYP MAX 24 UNIT Bits DATA FORMAT (PCM Mode) Audio data interface format fS Standard, I2S, left justified Audio data bit length 16-, 20-, 24-bit selectable Audio data format MSB first, 2s complement Sampling frequency System clock frequency 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 SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 DSD1794DB PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DIGITAL INPUT/OUTPUT Logic family VIH VIL Input logic level IIH IIL Input logic current VOH VOL Output logic level TTL compatible 2 0.8 VIN = VDD VIN = 0 V IOH = −2 mA IOL = 2 mA DYNAMIC PERFORMANCE (PCM MODE, 2-V RMS OUTPUT) (1)(2) THD+N at VOUT = 0 dB Channel separation Dynamic range Signal-to-noise ratio Channel separation 0.0004% VDC 0.0008% 0.0015% 123 127 127 127 123 127 EIAJ, A-weighted, fS = 192 kHz 127 120 dB 127 EIAJ, A-weighted, fS = 96 kHz fS = 44.1 kHz fS = 96 kHz µA 0.0008% EIAJ, A-weighted, fS = 192 kHz fS = 192 kHz Level linearity error VOUT = –120 dB DYNAMIC PERFORMANCE (PCM Mode, 4.5-V RMS Output) (1)(3) THD+N at VOUT = 0 dB 0.4 EIAJ, A-weighted, fS = 96 kHz EIAJ, A-weighted, fS = 44.1 kHz Signal-to-noise ratio 2.4 fS = 44.1 kHz fS = 96 kHz fS = 192 kHz EIAJ, A-weighted, fS = 44.1 kHz Dynamic range 10 –10 VDC dB 123 122 dB 120 ±1 fS = 44.1 kHz fS = 96 kHz 0.0004% fS = 192 kHz EIAJ, A-weighted, fS = 44.1 kHz 0.0015% dB 0.0008% 129 EIAJ, A-weighted, fS = 96 kHz 129 EIAJ, A-weighted, fS = 192 kHz 129 EIAJ, A-weighted, fS = 44.1 kHz 129 EIAJ, A-weighted, fS = 96 kHz EIAJ, A-weighted, fS = 192 kHz 129 fS = 44.1 kHz fS = 96 kHz 124 fS = 192 kHz 121 dB dB 129 123 dB (1) Filter condition: THD+N: 20-Hz HPF, 20-kHz apogee 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 33. (3) Dynamic performance and dc accuracy are specified at the output of the postamplifier as shown in Figure 34. Audio Precision and System Two are trademarks of Audio Precision, Inc. Other trademarks are the property of their respective owners. 3 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 DSD1794DB PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DYNAMIC PERFORMANCE (MONO MODE) (1)(2) THD+N at VOUT = 0 dB Dynamic range Signal-to-noise ratio fS = 44.1 kHz fS = 96 kHz 0.0004% fS = 192 kHz EIAJ, A-weighted, fS = 44.1 kHz 0.0015% 0.0008% 132 EIAJ, A-weighted, fS = 96 kHz 132 EIAJ, A-weighted, fS = 192 kHz 132 EIAJ, A-weighted, fS = 44.1 kHz 132 EIAJ, A-weighted, fS = 96 kHz 132 EIAJ, A-weighted, fS = 192 kHz 132 dB dB DSD MODE DYNAMIC PERFORMANCE (1) (3) (44.1 kHz, 64 FS) THD+N at FS 4.5 V rms Dynamic range –60 dB, EIAJ, A-weighted 0.0005% 128 dB Signal-to-noise ratio EIAJ, A-weighted 128 dB ANALOG OUTPUT Gain error –6 ±2 6 % 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) 7.8 mA p-p Center current At BPZ –6.2 mA DIGITAL FILTER PERFORMANCE ±0.004 De-emphasis error dB FILTER CHARACTERISTICS-1: SHARP ROLLOFF Pass band ±0.00001 dB 0.454 fS –3 dB Stop band 0.49 fS 0.546 fS ±0.00001 Pass-band ripple Stop-band attenuation Stop band = 0.546 fS –130 Delay time dB dB 55/fS s FILTER CHARACTERISTICS-2: SLOW ROLLOFF Pass band ±0.04 dB 0.254 fS –3 dB 0.46 fS Stop band 0.732 fS ±0.001 Pass-band ripple Stop-band attenuation Delay time Stop band = 0.732 fS –100 dB dB s (1) Filter condition: THD+N: 20-Hz HPF, 20-kHz apogee 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 34. (3) Dynamic performance and dc accuracy are specified at the output of the postamplifier as shown in Figure 35. 4 18/fS www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 DSD1794DB PARAMETER TEST CONDITIONS UNIT MIN TYP MAX 3 3.3 3.6 VDC 4.75 5 5.25 VDC fS = 44.1 kHz fS = 96 kHz 12 15 fS = 192 kHz fS = 44.1 kHz 45 fS = 96 kHz fS = 192 kHz 35 fS = 44.1 kHz fS = 96 kHz 205 fS = 192 kHz 335 POWER SUPPLY REQUIREMENTS VDD VCC1 VCC2L VCC2R Voltage range IDD Supply current (1) ICC Power dissipation (1) 23 33 mA 40 mA 37 250 250 mW TEMPERATURE RANGE Operation temperature –25 θJA Thermal resistance (1) Input is BPZ data. 28-pin SSOP 85 100 °C °C/W PIN ASSIGNMENTS DSD1794 (TOP VIEW) DSDL DSDR DBCK PLRCK PDATA PBCK SCK DGND VDD ADR0 ADR1 SCL SDA 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 SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 Terminal Functions TERMINAL NAME PIN I/O DESCRIPTIONS ADR1 11 I I2C address 0 (1) I2C address 1 (1) AGND1 19 − Analog ground (internal bias) AGND2 24 − Analog ground (internal bias) AGND3L 27 − Analog ground (L-channel DACFF) AGND3R 16 − DBCK 3 I Analog ground (R-channel DACFF) Bit clock input for DSD modes (1) DGND 8 − Digital ground DSDL 1 I/O DSDR 2 I/O 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 PBCK 20 − Output current reference bias pin 6 I PDATA 5 I Bit clock input. Connected to GND in DSD mode (1) Serial audio data input for PCM-format operation (1) PLRCK 4 I RST 14 I Left and right clock (fS) input for PCM-format operation. WDCK clock input for external DF mode. Connected to GND for DSD mode (1) Reset (1) SCL 12 I I2C clock (1) SCK 7 I SDA 13 I/O System clock input (1) I2C data (3) 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 ADR0 10 I L-channel audio data input when in DSD and external DF modes PCM-mode zero flag for L-channel when in zero-flag output mode (2) R-channel audio data input when in DSD and external DF modes (2) PCM-mode zero flag for R−channel when in zero-flag output mode VCOMR 21 − R-channel internal bias decoupling pin VDD 9 − Digital power supply, 3.3 V (1) Schmitt-trigger input, 5-V tolerant (2) Schmitt-trigger input and output. 5-V tolerant input, and CMOS output (3) Schmitt-trigger 5-V tolerant input and open-drain/3-state output 6 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 FUNCTIONAL BLOCK DIAGRAM IOUTL− DBCK DSDL DSDR PLRCK Current Segment DAC Audio Data Input I/F IOUTL+ 8 Oversampling Digital Filter and Function Control PBCK PDATA RST VCOML Advanced Segment DAC Modulator Bias and Vref SDA IREF VCOMR Current Segment DAC ADR1 VOUTR IOUTR+ I/V and Filter VCC1 AGND3R AGND3L AGND1 VDD DGND SCK AGND2 Power Supply System Clock Manager VCC2R ADR0 I/V and Filter IOUTR− Function Control I/F VCC2L SCL VOUTL 7 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 TYPICAL PERFORMANCE CURVES DIGITAL FILTER Digital Filter Response AMPLITUDE vs FREQUENCY 0 2 0.00002 −50 1 0.00001 −100 Amplitude − dB Amplitude − dB AMPLITUDE vs FREQUENCY −150 −1 −0.00001 −200 0 1 2 3 4 0 −2 −0.00002 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 −4 −50 Amplitude − dB Amplitude − dB −6 −100 −8 −10 −12 −14 −150 −16 −18 −200 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 SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 De-Emphasis Filter DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 20 0.020 fS = 32 kHz fS = 32 kHz 15 0.015 De-emphasis Error − dB De-emphasis Level − dB −2 −4 −6 10 0.010 5 0.005 0 −5 −0.005 −10 −0.010 −8 −15 −0.015 −10 −20 −0.020 0 2 4 6 8 10 12 14 0 2 4 6 f − Frequency − kHz 8 10 12 14 f − Frequency − kHz Figure 5 Figure 6 DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 20 0.020 fS = 44.1 kHz fS = 44.1 kHz 15 0.015 De-emphasis Error − dB De-emphasis Level − dB −2 −4 −6 10 0.010 5 0.005 0 −5 −0.005 −10 −0.010 −8 −15 −0.015 −10 −20 −0.020 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 SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 De-Emphasis Filter (Continued) DE-EMPHASIS LEVEL vs FREQUENCY DE-EMPHASIS ERROR vs FREQUENCY 0 20 0.020 fS = 48 kHz fS = 48 kHz 15 0.015 De-emphasis Error − dB De-emphasis Level − dB −2 −4 −6 10 0.010 5 0.005 0 −5 −0.005 −10 −0.010 −8 −15 −0.015 −10 −20 −0.020 0 2 4 6 8 10 12 14 f − Frequency − kHz Figure 9 10 16 18 20 22 0 2 4 6 8 10 12 14 f − Frequency − kHz Figure 10 16 18 20 22 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 ANALOG DYNAMIC PERFORMANCE Supply Voltage Characteristics TOTAL HARMONIC DISTORTION + NOISE vs SUPPLY VOLTAGE DYNAMIC RANGE vs SUPPLY VOLTAGE 132 130 fS = 96 kHz Dynamic Range − dB THD+N − Total Harmonic Distortion + Noise − % 0.01 fS = 192 kHz 0.001 fS = 96 kHz fS = 48 kHz 128 fS = 192 kHz 126 124 fS = 48 kHz 0.0001 4.50 4.75 5.00 5.25 122 4.50 5.50 VCC − Supply Voltage − V 4.75 Figure 11 130 130 128 Channel Separation − dB SNR − Signal-to-Noise Ratio − dB 5.50 CHANNEL SEPARATION vs SUPPLY VOLTAGE 132 fS = 96 kHz fS = 192 kHz fS = 48 kHz 126 124 122 4.50 5.25 Figure 12 SIGNAL-to-NOISE RATIO vs SUPPLY VOLTAGE 128 5.00 VCC − Supply Voltage − V 126 124 fS = 96 kHz fS = 48 kHz fS = 192 kHz 122 4.75 5.00 5.25 VCC − Supply Voltage − V 5.50 120 4.50 4.75 5.00 5.25 5.50 VCC − Supply Voltage − V Figure 13 Figure 14 NOTE: PCM mode, TA = 25°C, VDD = 3.3 V, measurement circuit is Figure 34 (VOUT = 4.5 V rms). 11 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 Temperature Characteristics TOTAL HARMONIC DISTORTION + NOISE vs FREE-AIR TEMPERATURE DYNAMIC RANGE vs FREE-AIR TEMPERATURE 132 130 Dynamic Range − dB THD+N − Total Harmonic Distortion + Noise − % 0.01 fS = 192 kHz 0.001 fS = 96 kHz 128 fS = 96 kHz fS = 48 kHz 126 124 fS = 48 kHz 0.0001 −50 −25 0 25 50 75 122 −50 100 TA − Free-Air Temperature − °C −25 0 75 100 CHANNEL SEPARATION vs FREE-AIR TEMPERATURE 132 130 130 128 fS = 96 kHz Channel Separation − dB SNR − Signal-to-Noise Ratio − dB 50 Figure 16 SIGNAL-to-NOISE RATIO vs FREE-AIR TEMPERATURE 128 fS = 192 kHz fS = 48 kHz 126 124 122 −50 25 TA − Free-Air Temperature − °C Figure 15 126 fS = 48 kHz 124 fS = 192 kHz fS = 96 kHz 122 −25 0 25 50 TA − Free-Air Temperature − °C 75 100 120 −50 −25 0 25 50 TA − Free-Air Temperature − °C Figure 17 NOTE: PCM mode, VDD = 3.3 V, VCC = 5 V, measurement circuit is Figure 34 (VOUT = 4.5 V rms). 12 fS = 192 kHz Figure 18 75 100 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 AMPLITUDE vs FREQUENCY AMPLITUDE vs FREQUENCY 0 0 −20 −20 −40 −60 Amplitude − dB Amplitude − dB −40 −80 −100 −120 −60 −80 −100 −120 −140 −140 −160 −180 −160 0 2 4 6 8 10 12 14 16 18 20 0 10 20 30 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 34. Figure 19. −60-db Output Spectrum, BW = 20 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 34. Figure 20. −60-db Output Spectrum, BW = 100 kHz TOTAL HARMONIC DISTORTION + NOISE vs INPUT LEVEL THD+N − Total Harmonic Distortion + Noise − % 10 1 0.1 0.01 0.001 0.0001 −100 −80 −60 −40 −20 0 Input Level − dBFS NOTE: PCM mode, fS = 48 kHz, TA = 25°C, VDD = 3.3 V, VCC = 5 V, measurement circuit is Figure 34. Figure 21. THD+N vs Input Level, PCM Mode 13 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 AMPLITUDE vs FREQUENCY 0 −20 Amplitude − dB −40 −60 −80 −100 −120 −140 −160 0 2 4 6 8 10 12 14 16 18 20 f − Frequency − kHz Figure 22. −60-dB Output Spectrum, DSD Mode AMPLITUDE vs FREQUENCY −130 −133 −136 Amplitude − dB −139 −142 −145 −148 −151 −154 −157 −160 0 2 4 6 8 10 12 14 16 18 20 f − Frequency − kHz Figure 23. −150-dB Output Spectrum, DSD Mono Mode NOTE: DSD mode (FIR-4), 32768 point 8 average, TA = 25°C, VDD = 3.3 V, VCC = 5 V, measurement circuit is Figure 35. 14 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 SYSTEM CLOCK AND RESET FUNCTIONS System Clock Input The DSD1794 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 DSD1794 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 24 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 DSD1794 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 8.192 384 fS 12.288 512 fS 16.384 768 fS 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 18.432 192 kHz 24.576 36.864 24.576 49.152(1) 36.864 73.728(1) 24.576 49.152(1) 36.864 73.728(1) (2) 32 kHz 44.1 kHz (2) (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. t(SCKH) H 2.0 V System Clock (SCK) 0.8 V L t(SCKL) PARAMETERS t(SCY) MIN MAX UNITS t(SCY) System clock pulse cycle time t(SCKH) System clock pulse duration, HIGH 13 ns 0.4t(SCY) ns t(SCKL) System clock pulse duration, LOW 0.4t(SCY) ns Figure 24. System Clock Input Timing Power-On and External Reset Functions The DSD1794 includes a power-on reset function. Figure 25 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 DSD1794 is set to its default reset state, as described in the MODE CONTROL REGISTERS section of this data sheet. The DSD1794 also includes an external reset capability using the RST input (pin 14). This allows an external controller or master reset circuit to force the DSD1794 to initialize to its default reset state. Figure 26 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 DSD1794 power up and system clock activation. 15 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 VDD 2.4 V (Max) 2.0 V (Typ) 1.6 V (Min) Reset Reset Removal Internal Reset 1024 System Clocks System Clock Figure 25. Power-On Reset Timing RST (Pin 14) 50 % of VDD t(RST) Reset Reset Removal Internal Reset 1024 System Clocks System Clock t(RST) PARAMETERS MIN Reset pulse duration, LOW 20 Figure 26. External Reset Timing 16 MAX UNITS ns www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 AUDIO DATA INTERFACE Audio Serial Interface The audio interface port is a 3-wire serial port. It includes PLRCK (pin 4), PBCK (pin 6), and PDATA (pin 5). PBCK is the serial audio bit clock, and it is used to clock the serial data present on PDATA into the serial shift register of the audio interface. Serial data is clocked into the DSD1794 on the rising edge of PBCK. PLRCK is the serial audio left/right word clock. The DSD1794 requires the synchronization of PLRCK and the system clock, but does not need a specific phase relation between PLRCK and the system clock. If the relationship between PLRCK and the system clock changes more than ±6 PBCK, internal operation is initialized within 1/fS and analog outputs are forced to the bipolar zero level until resynchronization between PLRCK and the system clock is completed. PCM Audio Data Formats and Timing The DSD1794 supports industry-standard audio data formats, including standard right-justified, I2S, and left-justified. The data formats are shown in Figure 28. 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 twos-complement, MSB-first audio data. Figure 27 shows a detailed timing diagram for the serial audio interface. 50% of VDD PLRCK t(BCH) t(BCL) t(LB) 50% of VDD PBCK t(BCY) t(BL) 50% of VDD PDATA t(DS) t(DH) PARAMETERS MIN MAX UNITS t(BCY) t(BCL) PBCK pulse cycle time 70 ns PBCK pulse duration, LOW 30 ns t(BCH) t(BL) PBCK pulse duration, HIGH 30 ns PBCK rising edge to PLRCK edge 10 ns t(LB) t(DS) PLRCK edge to PBCK rising edge 10 ns PDATA Setup time 10 ns t(DH) — PDATA hold time 10 ns PLRCK clock data 50% ± 2 bit clocks Figure 27. Timing of Audio Interface 17 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 (1) Standard Data Format (Right Justified); L-Channel = HIGH, R-Channel = LOW 1/fS PLRCK R-Channel L-Channel PBCK Audio Data Word = 16-Bit PDATA 14 15 16 1 2 MSB 15 16 1 2 15 16 LSB Audio Data Word = 20-Bit PDATA 18 19 20 1 2 19 20 1 2 19 20 LSB MSB Audio Data Word = 24-Bit PDATA 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 PLRCK R-Channel L-Channel PBCK Audio Data Word = 24-Bit PDATA 1 2 23 24 1 2 23 24 1 2 LSB MSB (3) I2S Data Format; L-Channel = LOW, R-Channel = HIGH 1/fS PLRCK L-Channel R-Channel PBCK Audio Data Word = 16-Bit PDATA 1 2 15 16 MSB 1 2 1 2 15 16 1 2 1 2 LSB Audio Data Word = 24-Bit PDATA 1 2 23 24 MSB LSB Figure 28. Audio Data Input Formats 18 23 24 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 External Digital Filter Interface and Timing The DSD1794 supports an external digital filter interface with 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, PLRCK (pin 4), PBCK (pin 6) and PDATA (pin 5) are defined as WDCK, the word clock; BCK, the bit clock; and DATA, the monaural data, respectively. 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 DSD1794. When the DFMS bit of control register 19 is set, the DSD1794 can process stereo data. In this case, DSDL (pin 1) and DSDR (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 DSD1794 supports the DSD-format interface operation, which includes out-of-band noise filtering using an internal analog FIR filter. The DSD-format interface consists of a 3-wire synchronous serial port, which includes DBCK (pin 3), DSDL (pin 1), and DSDR (pin 2). DBCK is the serial bit clock. DSDL and DSDR are the L-channel and R-channel DSD data inputs, respectively. They are clocked into the DSD1794 on the rising edge of DBCK. PLRCK (pin 4) and PBCK (pin 6) are connected to GND 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. SERIAL CONTROL INTERFACE (I2C) The DSD1794 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. Slave Address MSB 1 LSB 0 0 1 1 ADR1 ADR0 R/W The DSD1794 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 DSD1794s can be connected on the same bus at one time. Each DSD1794 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 DSD1794 supports only slave receivers and slave transmitters. 19 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 SDA SCL St 1−7 8 9 1−8 9 1−8 9 9 Slave Address R/W ACK DATA ACK DATA ACK ACK Sp R/W: Read Operation if 1; Otherwise, Write Operation ACK: Acknowledgement of a Byte if 0 DATA: 8 Bits (Byte) Start Condition Stop Condition Write operation Transmitter M M M S M S M S … S M Data Type St Slave Address R/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/W ACK DATA ACK DATA ACK … NACK Sp M: Master Device S: Slave Device St: Start Condition Sp: Stop Condition Figure 29. Basic I2C Framework Write Register A master can write to any DSD1794 registers using single or multiple accesses. The master sends a DSD1794 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 0x0. When undefined registers are accessed, the DSD1794 does not send an acknowledgement. Figure 30 is a diagram of the write operation. Transmitter Data Type M M St Slave Address M S M S M S M S … S M W ACK Reg Address ACK Write Data 1 ACK Write Data 2 ACK … ACK Sp M: Master Device S: Slave Device St: Start Condition W: Write ACK: Acknowledge Sp: Stop Condition Figure 30. Write Operation Read Register A master can read the DSD1794 register. The value of the register address is stored in an indirect index register in advance. The master sends a DSD1794 slave address with a read bit after storing the register address. Then the DSD1794 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 0x0. The DSD1794 outputs some data when the index register is 0x10 to 0x1F, even if it is not defined in Table 3. Figure 31 is a diagram of the read operation. 20 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 Transmitter M M M S M S M M M S S M … M M Data Type St Slave Address W ACK Reg Address ACK Sr Slave Address R ACK Data ACK … NACK Sp M: Master Device S: Slave Device St: Start Condition Sr: Repeated Start Condition ACK: Acknowledge Sp: Stop Condition NACK: Not Acknowledge W: Write R: Read NOTE: The slave address after the repeat start condition must be the same as the previous slave address. Figure 31. Read Operation Noise Suppression The DSD1794 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 DSD1794 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 DSD1794 erroneously detects a start or stop condition. 21 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 TIMING DIAGRAM Start Stop Repeated Start 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) Setup time for (repeated) start condition Hold time for (repeated) start condition t(D-SU) 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) Pulse duration of suppressed spike CONDITIONS MIN MAX Standard 100 Fast 400 Standard 4.7 Fast 1.3 Standard 4.7 Fast 1.3 Standard 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 Standard Fast ns ns ns ns ns µs 4 600 Fast ns ns 400 pF 50 ns Standard 22 Fast 0.2 VDD V www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 MODE CONTROL REGISTERS User-Programmable Mode Controls The DSD1794 includes a number of user-programmable functions which are accessed via mode control registers. The registers are programmed using the serial control interface, discussed in the SERIAL CONTROL INTERFACE (I 2C) section of this data sheet. Table 2 lists the available mode-control functions, along with their default reset conditions and associated register index. Table 2. 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 24-bit I2S format Register 18 ATLD yes 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—Mute disabled, enabled Mute disabled Register 18 MUTE yes Output phase reversal—Normal, reverse Normal Register 19 REV yes Attenuation speed selection ×1 fS, ×(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 Zero flag pin operation control DSD data input, zero flag output DSD data input Register 19 ZOE 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 DSD interface mode control DSD enabled, disabled Disabled Register 20 DSD Digital-filter bypass control DF enabled, DF bypass DF enabled Register 20 DFTH 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] 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 yes yes(1) yes yes yes yes yes yes yes yes yes yes yes yes yes Function available only for read Zero detection flag Not zero = 0 Register 22 ZFGL (for L-ch) Not zero, zero detected Zero detected = 1 ZFGR (for R-ch) (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 23 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 Register Map The mode control register map is shown in Table 3. 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. Register 22 is read-only. Table 3. 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 ZOE 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 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. Table 4 shows attenuation levels for various settings. Table 4. Digital Attenuation Levels 24 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 SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 For the external digital filter interface mode (DFTH mode), this register is operated as shown in the Application for Interfacing With an External Digital Filter section of this data sheet. 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. 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. 25 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 MUTE disabled (default) MUTE = 1 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 ZOE 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 PLRCK (default) 01 PLRCK/2 10 PLRCK/4 11 PLRCK/8 The ATS[1:0] bits are used to select the rate at which the attenuator is decremented/incremented during level transitions. 26 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 digital audio data is present on the input. ZOE: Zero Flag Pin Operation Control This bit is available for read and write. Default value: 0 ZOE = 0 DSD data input (default) ZOE = 1 Zero flag output The ZOE bit is used to change the DSDL (pin 1) and DSDR (pin 2) pin assignments. When the ZOE bit is set to 0, DSDL and DSDR are inputs for L-channel and R-channel data. When the ZOE bit is set to 1, DSDL and DSDR become outputs for the L-channel and R-channel zero flags, respectively. See the PCMZ and DZ[1:0] bit descriptions of register 21. 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 PDATA (pin 5) only, therefore the DSD1794 operates as a monaural DAC. When DFMS is set to 1, the DSD1794 can operate as a stereo DAC with inputs of L-channel and R-channel data on DSDL (pin 1) and DSDR (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 DSD1794 detects zero data in both channels continuously for 1024 sampling periods (1/fS). The infinite zero detect mute function does not work in the DSD mode. 27 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 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 DSD1794 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 the 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 This bit is available when MONO = 1. CHSL = 0 L-channel selected (default) CHSL = 1 R-channel selected The CHSL bit selects L-channel or R-channel data to be used in monaural mode. 28 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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. The DSD1794 sets zero flags when the number of 1s and 0s are equal in every 8 bits of DSD input data, or the DSD input data is 1001 0110 continuously for 200 ms. 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. The DSD1794 sets the zero flags when the input data is continuously zero for 1024 LRCKs in the PCM mode or 1024 × 8 WCKs in the external filter 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 29 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 R: Read Mode Select Value is always 1, specifying the readback mode. 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 When the DSD1794 detects that audio input data is continuously zero, the ZFGx bit is set to 1 for the corresponding channel(s). TYPICAL CONNECTION DIAGRAM Cf 5V Rf 0.1 µF DSD Audio Data Source PCM Audio Data Source 0.1 µF Controller 1 DSDL VCC2L 28 2 DSDR AGND3L 27 3 DBCK IOUTL− 26 4 PLRCK IOUTL+ 25 5 PDATA AGND2 24 6 PBCK VCC1 23 7 SCK VCOML 22 8 DGND 9 VDD DSD1794 VCOMR 21 IREF 20 10 ADR0 AGND1 19 11 ADR1 IOUTR− 18 12 SCL IOUTR+ 17 13 SDA AGND3R 16 14 RST VCC2R 15 + 10 µF − + Cf Rf 5V − 47 µF + − + Cf Rf 5V − 10 µF + 3.3 V + 10 µF Figure 32. Typical Application Circuit 30 VOUT R-Channel Rf 10 kΩ + Differential to Single Converter With Low-Pass Filter Cf 47 µF 0.1 µF VOUT L-Channel + + 10 µF + Differential to Single Converter With Low-Pass Filter www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 APPLICATION INFORMATION APPLICATION CIRCUIT The design of the application circuit is very important in order to actually realize the high S/N ratio of which the DSD1794 is capable. This is because noise and distortion that are generated in an application circuit are not negligible. In the circuit of Figure 33, the output level is 2 V RMS and 127 dB S/N is achieved. The circuit of Figure 34 can realize the highest performance. In this case the output level is set to 4.5 V rms and 129 dB S/N is achieved (stereo mode). In monaural mode, if the output of the L-channel and R-channel is used as a balanced output, 132 dB S/N is achieved (see Figure 36). Figure 35 shows a circuit for the DSD mode, which is a 4th-order LPF in order to reduce the out-of-band noise. I/V Section The current of the DSD1794 on each of the output pins (IOUTL+, IOUTL–, IOUTR+, IOUTR–) is 7.8 mA p-p at 0 dB (full scale). The voltage output level of the I/V converter (Vi) is given by following equation: Vi = 7.8 mA p−p × Rf (Rf: feedback resistance of I/V converter) An NE5534 op amp 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 op amp affects the audio dynamic performance of the I/V section. Differential Section The DSD1794 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 op amp recommended for the differential circuit is the Linear Technology LT1028, because its input noise is low. 31 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 C1 2200 pF R1 750 Ω VCC VCC C11 0.1 µF C17 22 pF 7 IOUT− 5 2 8 − 3 R5 270 Ω 6 + C3 2700 pF R3 560 Ω C19 33 pF 7 2 U1 NE5534 4 C15 0.1 µF 3 5 − 6 + 4 C12 0.1 µF VEE R4 560 Ω R6 270 Ω U3 LT1028 C16 0.1 µF C4 2700 pF VEE C2 2200 pF R2 750 Ω VCC C13 0.1 µF C18 22 pF 7 IOUT+ 2 3 5 − VCC = 15 V VEE = −15 V fC = 217 kHz 8 6 + 4 U2 NE5534 C14 0.1 µF VEE Figure 33. Measurement Circuit for PCM, VOUT = 2 V RMS 32 R7 100 Ω www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 C1 2200 pF R1 820 Ω VCC VCC C11 0.1 µF C17 22 pF 7 IOUT− 5 2 8 − 3 R5 360 Ω 6 + C3 2700 pF R3 360 Ω C19 33 pF 7 2 U1 NE5534 4 C15 0.1 µF 3 5 − 6 + 4 C12 0.1 µF VEE R4 360 Ω R6 360 Ω R7 100 Ω U3 LT1028 C16 0.1 µF C4 2700 pF VEE C2 2200 pF R2 820 Ω VCC C13 0.1 µF C18 22 pF 7 IOUT+ 2 3 VCC = 15 V VEE = −15 V fC = 162 kHz 5 − 8 6 + 4 U2 NE5534 C14 0.1 µF VEE Figure 34. Measurement Circuit for PCM, VOUT = 4.5 V RMS 33 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 C1 2200 pF R1 820 Ω VCC VCC C11 0.1 µF C17 22 pF 7 IOUT− 5 2 8 − 3 R5 330 Ω 6 + R3 110 Ω R10 68 Ω C3 18000 pF U1 NE5534 4 R8 220 Ω C5 10000 pF C15 0.1 µF C19 33 pF 7 2 C4 47000 pF 3 5 − 6 + 4 C12 0.1 µF VEE R4 110 Ω R9 220 Ω R6 330 Ω R11 68 Ω C14 0.1 µF C6 10000 pF VEE C2 2200 pF R2 820 Ω VCC C13 0.1 µF 7 IOUT+ 2 3 VCC = 15 V VEE = −15 V fC = 38 kHz C18 22 pF 5 − 8 6 + 4 U2 NE5534 C14 0.1 µF VEE Figure 35. Measurement Circuit for DSD 34 U3 LT1028 R7 100 Ω www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 IOUTL− (Pin 26) IOUT− OUT+ Figure 34 Circuit IOUTL+ (Pin 25) IOUT+ 3 1 2 IOUTR− (Pin 18) IOUT− OUT− Figure 34 Circuit IOUTR+ (Pin 17) Balanced Out IOUT+ Figure 36. Measurement Circuit for Monaural Mode APPLICATION FOR EXTERNAL DIGITAL FILTER INTERFACE DFMS = 0 External Filter Device DSD1794 1 DSDL 2 DSDR 3 DBCK WDCK (Word Clock) 4 PLRCK DATA 5 PDATA BCK 6 PBCK SCK 7 SCK DFMS = 1 External Filter Device DSD1794 DATA_L 1 DSDL DATA_R 2 DSDR 3 DBCK 4 PLRCK 5 PDATA BCK 6 PBCK SCK 7 SCK WDCK (Word Clock) Figure 37. Connection Diagram for External DIgital Filter (Internal DF Bypass Mode) Application 35 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 DSD1794. The DSD1794 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 bit 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 37. The word clock (WDCK) signal must be operated at 8× or 4× the desired sampling frequency, fS. System Clock (SCK) and Interface Timing The DSD1794 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, and DATA is shown in Figure 39. Audio Format The DSD1794 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 38. The audio format is selected by the FMT[2:0] bits of control register 18. 1/4 fS or 1/8 fS WDCK BCK Audio Data Word = 16-Bit DATA 15 16 1 2 3 4 MSB 5 6 7 8 9 10 11 12 13 14 15 16 LSB Audio Data Word = 20-Bit DATA 19 20 1 2 3 4 MSB 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 LSB Audio Data Word = 24-Bit DATA 23 24 1 2 3 MSB 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 LSB Figure 38. Audio Data Input Format for External Digital Filter (Internal DF Bypass Mode) Application 36 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 50% of VDD WDCK t(BCH) t(BCL) t(LB) 50% of VDD BCK t(BCY) t(BL) 50% of VDD DATA t(DS) t(DH) PARAMETER MIN t(BCY) BCK pulse cycle time t(BCL) BCK pulse duration, LOW 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 setup time 5 ns t(DH) DATA hold time 5 ns Figure 39. Audio Interface Timing for External Digital Filter (Internal DF Bypass Mode) Application Functions Available in the External Digital Filter Mode The external digital filter mode allows access to the majority of the DSD1794 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: 1 indicates that the bit is required for selection of external digital filter mode. − indicates that 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 37 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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. APPLICATION FOR DSD FORMAT (DSD MODE) INTERFACE DSD Decoder DSD1794 DATA_L 1 DSDL DATA_R 2 DSDR Bit Clock 3 DBCK 4 PLRCK 5 PDATA 6 PBCK 7 SCK System Clock (1) (1) The system clock is necessary for the initilaization sequence and the I2C interface operation. Figure 40. 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 to convert the 1-bit oversampled data stream to the analog domain. 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 DSD1794 erroneously detects the TDMCA mode, and commands are not accepted through the serial control interface. Pin Assignment When DSD Format Interface D DSDL (pin 1): L-channel DSD data input D DSDR (pin 2): R-channel DSD data input D DBCK (pin 3): Bit clock (BCK) for DSD data Super Audio CD is a trademark of Sony Kabushiki Kaisha TA Sony Corporation, Japan. 38 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 t = 1/(64 × 44.1 kHz) DBCK DSDL DSDR D0 D1 D2 D3 D4 Figure 41. Normal Data Output Form From DSD Decoder t(BCH) t(BCL) 50% of VDD DBCK t(BCY) DSDL DSDR 50% of VDD 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 t(DH) DSDL, DSDR hold time (1) 2.8224 MHz × 4. (2.8224 MHz = 64 × 44.1 kHz. This value is specified as a sampling rate of DSD.) MIN 85(1) MAX UNITS ns 30 ns 30 ns 10 ns 10 ns Figure 42. Timing for DSD Audio Interface 39 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 43. DSD Filter-1, Low BW Figure 44. DSD Filter-1, High BW GAIN vs FREQUENCY GAIN vs FREQUENCY 0 0 −1 −10 −2 −20 Gain − dB Gain − dB fc = 77 kHz Gain(1) = −6 dB −3 −30 −4 −40 −5 −50 −6 −60 0 50 100 150 200 0 500 f − Frequency − kHz Figure 45. DSD Filter-2, Low BW 1000 f − Frequency − kHz Figure 46. 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. 40 1500 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 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 −60 −6 0 50 100 150 0 200 500 1000 1500 f − Frequency − kHz f − Frequency − kHz Figure 47. DSD Filter-3, Low BW Figure 48. 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 49. DSD Filter-4, Low BW 500 1000 1500 f − Frequency − kHz Figure 50. 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. 41 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 DSD MODE CONFIGURATION AND FUNCTION CONTROLS Configuration for the DSD Interface Mode 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: − indicates that 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 TYPICAL PERFORMANCE CURVES 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 to 1. Requirements for System Clock The bit clock (DBCK) for the DSD mode is required at pin 3 of the DSD1794. 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 same setup-and hold-time specifications as shown in Figure 42. 42 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 THEORY OF OPERATION Upper 6 Bits ICOB Decoder 0−62 Level 0−66 Advanced DWA Digital Input 24 Bits 8 fS MSB and Lower 18 Bits 3rd-Order 5-Level Sigma-Delta Current Segment DAC Analog Output 0−4 Level Figure 51. Advanced Segment DAC The DSD1794 uses TI’s advanced segment DAC architecture to achieve excellent dynamic performance and improved tolerance to clock jitter. The DSD1794 provides balanced current outputs. Digital input data via the digital filter is separated into 6 upper bits and 18 lower bits. The 6 upper bits are converted to inverted complementary offset binary (ICOB) code. The lower 18 bits, associated with the MSB, are processed by a five-level third-order delta-sigma modulator operated at 64 fS by default. The 1 level of the modulator is equivalent to the 1 LSB of the ICOB code converter. The data groups processed in the ICOB converter and third-order delta-sigma modulator are summed together to an up to 66-level digital code, and then processed by data-weighted averaging (DWA) to reduce the noise produced by element mismatch. The data of up to 66 levels from the DWA is converted to an analog output in the differential-current segment section. This architecture has overcome the various drawbacks of conventional multibit processing and also achieves excellent dynamic performance. 43 www.ti.com SLES077A − MARCH 2003 − REVISED NOVEMBER 2003 Analog output The following table and Figure 52 show the relationship between the digital input code and analog output. IOUTN [mA] IOUTP [mA] VOUTN [V] VOUTP [V] 800000 (–FS) 000000 (BPZ) 7FFFFF (+FS) –2.3 –6.2 –10.1 –10.1 –6.2 –2.3 –1.725 –4.65 –7.575 –7.575 –4.65 –1.725 VOUT [V] –2.821 0 2.821 NOTE: VOUTN is the output of U1, VOUTP is the output of U2, and VOUT is the output of U3 in the application circuit of Figure 33. OUTPUT CURRENT vs INPUT CODE 0 IO − Output Current − mA −2 IOUTN −4 −6 −8 −10 IOUTP −12 800000(−FS) 000000(BPZ) 7FFFFF(+FS) Input Code − Hex Figure 52. The Relationship Between Digital Input and Analog Output 44 PACKAGE OPTION ADDENDUM www.ti.com 19-May-2005 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty DSD1794DB ACTIVE SSOP DB 28 47 Pb-Free (RoHS) CU SNBI Level-1-250C-UNLIM DSD1794DBR ACTIVE SSOP DB 28 2000 Pb-Free (RoHS) CU SNBI Level-1-250C-UNLIM Lead/Ball Finish MSL Peak Temp (3) (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 MECHANICAL DATA MSSO002E – JANUARY 1995 – REVISED DECEMBER 2001 DB (R-PDSO-G**) PLASTIC SMALL-OUTLINE 28 PINS SHOWN 0,38 0,22 0,65 28 0,15 M 15 0,25 0,09 8,20 7,40 5,60 5,00 Gage Plane 1 14 0,25 A 0°–ā8° 0,95 0,55 Seating Plane 2,00 MAX 0,10 0,05 MIN PINS ** 14 16 20 24 28 30 38 A MAX 6,50 6,50 7,50 8,50 10,50 10,50 12,90 A MIN 5,90 5,90 6,90 7,90 9,90 9,90 12,30 DIM 4040065 /E 12/01 NOTES: A. B. C. D. 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