PCM1742 PCM 174 2 www.ti.com 24-Bit, 192kHz Sampling Enhanced Multilevel, Delta-Sigma, Audio DIGITAL-TO-ANALOG CONVERTER 5V TOLERANT DIGITAL INPUTS FEATURES SMALL SSOP-16 PACKAGE 24-BIT RESOLUTION SAME PACKAGE SIZE AS SOP-8 ANALOG PERFORMANCE (VCC = +5V): Dynamic Range: 106dB typ (PCM1742KE) 100dB typ (PCM1742E) SNR: 106dB typ (PCM1742KE) 100dB typ (PCM1742E) THD+N: 0.002% typ (PCM1742KE) 0.003% typ (PCM1742E) Full-Scale Output: 3.1Vp-p typ APPLICATIONS AV RECEIVERS DVD MOVIE PLAYERS DVD ADD-ON CARDS FOR HIGH-END PCs DVD AUDIO PLAYERS HDTV RECEIVERS 4x/8x OVERSAMPLING DIGITAL FILTER: Stopband Attenuation: -55dB Passband Ripple: 0.03dB CAR AUDIO SYSTEMS SAMPLING FREQUENCY: 5kHz to 200kHz OTHER APPLICATIONS REQUIRING 24-BIT AUDIO SYSTEM CLOCK: 128, 192, 256, 384, 512, 768fS with Auto Detect DESCRIPTION ACCEPTS 16-, 18-, 20-, AND 24-BIT AUDIO DATA DATA FORMATS: Standard, I2S, and LeftJustified USER-PROGRAMMABLE MODE CONTROLS: Digital Attenuation: 0dB to -63dB, 0.5dB/Step Digital De-Emphasis Digital Filter Roll-Off: Sharp or Slow Soft Mute Zero Flags for Each Output DUAL-SUPPLY OPERATION: +5V Analog, +3.3V Digital Copyright (c) 2000, Texas Instruments Incorporated The PCM1742 is a CMOS, monolithic, integrated circuit which includes stereo Digital-to-Analog Converters (DACs) and support circuitry in a small SSOP-16 package. The data converters utilize Texas Instrument's enhanced multilevel delta-sigma architecture that employs fourthorder noise shaping and 8-level amplitude quantization to achieve excellent dynamic performance and improved tolerance to clock jitter. The PCM1742 accepts industry standard audio data formats with 16- to 24-bit data, providing easy interfacing to audio DSP and decoder chips. Sampling rates up to 200kHz are supported. A full set of user-programmable functions are accessible through a 3-wire serial control port that supports register write functions. SBAS176 Printed in U.S.A. December, 2000 SPECIFICATIONS All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, fS = 44.1kHz, system clock = 384fS, and 24-bit data, unless otherwise noted. PCM1742E PCM1742KE PARAMETER CONDITIONS MIN RESOLUTION DYNAMIC PERFORMANCE(4) (5) PCM1742E THD+N at VOUT = 0dB THD+N at VOUT = -60dB Dynamic Range Signal-to-Noise Ratio Channel Separation Level Linearity Error PCM1742KE THD+N at VOUT = 0dB THD+N at VOUT = -60dB Dynamic Range Signal-to-Noise Ratio Channel Separation Level Linearity Error DC ACCURACY Gain Error Gain Mismatch, Channel-to-Channel Bipolar Zero Error ANALOG OUTPUT Output Voltage Center Voltage Load Impedance DIGITAL FILTER PERFORMANCE Filter Characteristics 1, Sharp Roll-Off Passband Passband Stopband Passband Ripple Stopband Attenuation Stopband Attenuation 2 MAX 24 DATA FORMAT Audio Data Interface Formats Audio Data Bit Length Audio Data Format Sampling Frequency (fS) System Clock Frequency DIGITAL INPUT/OUTPUT Logic Family Input Logic Level VIH VIL Input Logic Current IIH(1) IIL(1) IIH(2) IIL(2) Output Logic Level VOH(3) VOL(3) TYP UNITS Bits Standard, I2S, Left-Justified 16-, 18-, 20-, 24-Bits Selectable MSB-First, Binary Two's Complement 5 100 256, 384, 512, 768fS kHz TTL-Compatible 2.0 VIN = VDD VIN = 0V VIN = VDD VIN = 0V IOH = -2mA IOL = +2mA fS = 44.1kHz fS = 96kHz fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz EIAJ, A-Weighted, fS = 44.1kHz A-Weighted, fS = 96kHz A-Weighted, fS = 192kHz EIAJ, A-Weighted, fS = 44.1kHz A-Weighted, fS = 96kHz A-Weighted, fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz VOUT = -90dB fS = 44.1kHz fS = 96kHz fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz EIAJ, A-Weighted, fS = 44.1kHz A-Weighted, fS = 96kHz A-Weighted, fS = 192kHz EIAJ, A-Weighted, fS = 44.1kHz A-Weighted, fS = 96kHz A-Weighted, fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz VOUT = -90dB 65 94 94 91 100 100 97 Full Scale (0dB) 10 -10 100 -10 A A A A 1.0 VDC VDC 0.003 0.004 0.005 1.2 1.6 1.8 100 98 96 100 98 96 98 96 94 0.5 0.008 % % % % % % dB dB dB dB dB dB dB dB dB dB 0.002 0.003 0.004 0.65 0.8 0.95 106 104 102 106 104 102 103 101 100 0.5 0.006 % % % % % % dB dB dB dB dB dB dB dB dB dB 1.0 1.0 30 6 3 60 % of FSR % of FSR mV 62% of VCC 50% VCC Vp-p VDC k 5 0.03dB -3dB 0.454fS 0.487fS 0.546fS Stopband = 0.546fS Stopband = 0.567fS VDC VDC 2.4 VOUT = 0.5 VCC at Bipolar Zero AC Load 0.8 -50 -55 0.03 dB dB dB PCM1742 SBAS176 SPECIFICATIONS (Cont.) All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, system clock = 384fS (fS = 44.1kHz), and 24-bit data, unless otherwise noted. PCM1742E PCM1742KE PARAMETER CONDITIONS DIGITAL FILTER PERFORMANCE (Cont.) Filter Characteristics 2, Slow Roll-Off Passband Passband Stopband Passband Ripple Stopband Attenuation Delay Time De-Emphasis Error TYP 0.5dB -3dB Stopband = 0.884fS +3.0 +4.5 Power Dissipation 20/fS 0.1 -0.03 -0.20 dB dB -25 JA UNITS dB dB sec dB +3.3 +5.0 6.0 13 16 8.5 9.0 9.0 62 88 98 fS = 44.1kHz fS = 96kHz fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz fS = 44.1kHz fS = 96kHz fS = 192kHz ICC 0.5 -40 f = 20kHz f = 44kHz POWER SUPPLY REQUIREMENTS(4) Voltage Range, VDD VCC Supply Current, IDD MAX 0.198fS 0.390fS 0.884fS ANALOG FILTER PERFORMANCE Frequency Response TEMPERATURE RANGE Operation Temperature Thermal Resistance MIN +3.6 +5.5 10 13 98 +85 SSOP-16 115 VDC VDC mA mA mA mA mA mA mW mW mW C C/W NOTES: (1) Pins 1, 2, 3, 16 (SCK, BCK, LRCK, DATA). (2) Pins 13-15 (MD, MC, ML). (3) Pins 11, 12 (ZEROR, ZEROL). (4) Analog performance specifications are tested with a Shibasoku #725 THD Meter with 400Hz HPF on, 30kHz LPF on, and an average mode with 20kHz bandwidth limiting. The load connected to the analog output is 5k or larger, via capacitive coupling. (5) Conditions in 192kHz operation are: system clock = 128fS and oversampling rate = 64fS of Register 18. ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS Power Supply Voltage, VDD .............................................................. +4.0V VCC .............................................................. +6.5V Ground Voltage Differences .............................................................. 0.1V Digital Input Voltage ................................................ -0.3V to (6.5V + 0.3V) Input Current (except power supply) ............................................... 10mA Ambient Temperature Under Bias .................................. -40C to +125C Storage Temperature ...................................................... -55C to +150C Junction Temperature .................................................................... +150C Lead Temperature (soldering, 5s) ................................................. +260C Package Temperature (IR reflow, 10s) .......................................... +235C This integrated circuit can be damaged by ESD. Burr-Brown 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. PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER PCM1742E SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER(1) TRANSPORT MEDIA PCM1742E PCM1742E/2K PCM1742KE PCM1742KE/2K Rails Tape and Reel Rails Tape and Reel SSOP-16 322 -25C to +85C PCM1742E " " " " " PCM1742KE SSOP-16 322 -25C to +85C PCM1742KE " " " " " NOTE: (1) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /2K indicates 2000 devices per reel). Ordering 2000 pieces of "PCM1742E/2K" will yield a single 2000-piece Tape and Reel. PCM1742 SBAS176 3 BLOCK DIAGRAM BCK Audio Serial Port LRCK 4x/8x Oversampling Digital Filter with Function Controller DATA ML VOUTL Low-Pass Filter Enhanced Multilevel Delta-Sigma Modulator VCOM Serial Control Port MC Output Amp and DAC Output Amp and DAC Low-Pass Filter VOUTR MD System Clock VCC AGND PIN ASSIGNMENTS TOP VIEW SSOP BCK 1 16 SCK DATA 2 15 ML LRCK 3 14 MC 4 VDD ZEROR ZEROL PIN CONFIGURATION DGND Power Supply Zero Detect DGND System Clock Manager SCK 13 MD PCM1742 VDD 5 12 ZEROL/NA VCC 6 11 ZEROR/ZEROA VOUTL 7 10 VCOM VOUTR 8 9 AGND PIN NAME TYPE 1 BCK IN Audio Data Bit Clock Input.(1) FUNCTION 2 DATA IN Audio Data Digital Input.(1) 3 LRCK IN L-Channel and R-Channel Audio Data Latch Enable Input.(1) 4 DGND - Digital Ground 5 VDD - Digital Power Supply, +3.3V 6 VCC - 7 VOUTL OUT 8 VOUTR OUT 9 AGND - Analog Ground - Common Voltage Decoupling. 10 VCOM 11 ZEROR/ ZEROA OUT Analog Power Supply, +5V Analog Output for L-Channel. Analog Output for R-Channel. Zero Flag Output for R-Channel/Zero Flag Output for L/R-Channel. 12 ZEROL/NA OUT 13 MD IN Mode Control Data Input.(2) 14 MC IN Mode Control Clock Input.(2) 15 ML IN Mode Control Latch Input.(2) 16 SCK IN System Clock Input. Zero Flag Output for L-Channel/No Assign. NOTES: (1) Schmitt-trigger input, 5V tolerant. (2) Schmitt-trigger with internal pull-down, 5V tolerant. 4 PCM1742 SBAS176 TYPICAL PERFORMANCE CURVES All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, system clock = 384fS (fS = 44.1kHz), and 24-bit input data, unless otherwise noted. DIGITAL FILTER Digital Filter (De-Emphasis Off) FREQUENCY RESPONSE PASSBAND (Sharp Roll-Off) FREQUENCY RESPONSE (Sharp Roll-Off) 0 0.05 0.04 -20 0.03 0.02 Amplitude (dB) Amplitude (dB) -40 -60 -80 -100 0.01 0 -0.01 -0.02 -0.03 -120 -0.04 -0.05 -140 0 1 2 3 4 0 0.1 0.2 Frequency (x fS) 0.3 0.4 0.5 Frequency (x fS) FREQUENCY RESPONSE (Slow Roll-Off) TRANSITION CHARACTERISTICS (Slow Roll-Off) 0 5 4 -20 3 2 Amplitude (dB) Amplitude (dB) -40 -60 -80 -100 1 0 -1 -2 -3 -120 -4 -5 -140 0 1 2 3 0 4 0.1 0.2 0.3 0.4 0.5 Frequency (x fS) Frequency (x fS) De-Emphasis DE-EMPHASIS ERROR (fS = 32kHz) 0.5 -1.0 0.4 -2.0 0.3 -3.0 0.2 -4.0 0.1 Error (dB) Level (dB) DE-EMPHASIS (fS = 32kHz) 0.0 -5.0 -6.0 0.0 -0.1 -7.0 -0.2 -8.0 -0.3 -9.0 -0.4 -0.5 -10.0 0 2 4 6 8 Frequency (kHz) PCM1742 SBAS176 10 12 14 0 2 4 6 8 10 12 14 Frequency (kHz) 5 TYPICAL PERFORMANCE CURVES (Cont.) All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, system clock = 384fS (fS = 44.1kHz), and 24-bit input data, unless otherwise noted. De-Emphasis (Cont.) DE-EMPHASIS ERROR (fS = 44.1kHz) 0.5 -1.0 0.4 -2.0 0.3 -3.0 0.2 -4.0 0.1 Error (dB) Level (dB) DE-EMPHASIS (fS = 44.1kHz) 0.0 -5.0 -6.0 0.0 -0.1 -7.0 -0.2 -8.0 -0.3 -9.0 -0.4 -0.5 -10.0 0 2 4 6 8 10 12 14 16 18 0 20 2 4 6 DE-EMPHASIS (fS = 48kHz) 10 12 14 16 18 20 18 22 DE-EMPHASIS ERROR (fS = 48kHz) 0.0 0.5 -1.0 0.4 -2.0 0.3 -3.0 0.2 -4.0 0.1 Error (dB) Level (dB) 8 Frequency (kHz) Frequency (kHz) -5.0 -6.0 0.0 -0.1 -7.0 -0.2 -8.0 -0.3 -9.0 -0.4 -10.0 -0.5 0 2 4 6 8 10 12 14 16 18 22 0 2 4 6 Frequency (kHz) 8 10 12 14 16 Frequency (kHz) ANALOG DYNAMIC PERFORMANCE All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, and 24-bit input data, unless otherwise noted. Conditions in 192kHz operation are: system clock = 128fS and oversampling rate = 64fS of Register 18. Supply-Voltage Characteristics DYNAMIC RANGE vs VCC (VDD = 3.3V) THD+N vs VCC (VDD = 3.3V) 10 110 -60dB/192kHz, 384fS -60dB/96kHz, 384fS 108 44.1kHz, 384fS Dynamic Range (dB) THD+N (%) 1 -60dB/44.1kHz, 384fS 0.1 0dB/192kHz, 384fS 0dB/96kHz, 384fS 0.01 96kHz, 384fS 104 192kHz, 384fS 102 100 98 0dB/44.1kHz, 384fS 96 0.001 2.4 2.7 3 3.3 VCC (V) 6 106 3.6 3.9 4 4.5 5 5.5 6 VCC (V) PCM1742 SBAS176 TYPICAL PERFORMANCE CURVES (Cont.) All specifications at TA = +25C, VCC = 5.0V, VDD = 3.3V, and 24-bit input data, unless otherwise noted. Conditions in 192kHz operation are: system clock = 128fS and oversampling rate = 64fS of Register 18. Supply-Voltage Characteristics (Cont.) SNR vs VCC (VDD = 3.3V) CHANNEL SEPARATION vs VCC (VDD = 3.3V) 110 110 108 Channel Separation (dB) 106 SNR (dB) 108 44.1kHz, 384fS 96kHz, 384fS 104 192kHz, 384fS 102 100 98 106 44.1kHz, 384fS 104 102 96kHz, 384fS 100 192kHz, 384fS 98 96 96 4 4.5 5 5.5 6 4 4.5 5 VCC (V) 5.5 6 VCC (V) Temperature Characteristics DYNAMIC RANGE vs TA THD+N vs TA 10 110 -60dB/192kHz, 384fS -60dB/96kHz, 384fS 108 Dynamic Range (dB) THD+N (%) 1 -60dB/44.1kHz, 384fS 0.1 0dB/96kHz, 384fS 0.01 0.001 0dB/96kHz, 384fS 0dB/44.1kHz, 384fS 44.1kHz, 384fS 106 96kHz, 384fS 104 192kHz, 384fS 102 100 98 96 0.0001 -50 -25 0 25 50 75 100 -50 -25 0 Temperature (C) SNR vs TA 50 75 100 75 100 CHANNEL SEPARATION vs TA 110 110 108 108 Channel Separation (dB) 44.1kHz, 384fS 106 96kHz, 384fS SNR (dB) 25 Temperature (C) 104 192kHz, 384fS 102 100 98 106 44.1kHz, 384fS 104 96kHz, 384fS 102 100 192kHz, 384fS 98 96 96 -50 -25 0 25 Temperature (C) PCM1742 SBAS176 50 75 100 -50 -25 0 25 50 Temperature (C) 7 SYSTEM CLOCK AND RESET FUNCTIONS POWER-ON RESET FUNCTIONS The PCM1742 includes a power-on reset function, as shown in Figure 2. With the system clock active, and VDD > 2.0V (typical 1.6V to 2.4V), the power-on reset function will be enabled. The initialization sequence requires 1024 system clocks from the time VDD > 2.0V. After the initialization period, the PCM1742 will be set to its reset default state, as described in the Mode Control Register section of this data sheet. SYSTEM CLOCK INPUT The PCM1742 requires a system clock for operating the digital interpolation filters and multilevel delta-sigma modulators. The system clock is applied at the SCK input (pin 16). Table I shows examples of system clock frequencies for common audio sampling rates. Figure 1 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. The PLL1700 multiclock generator from Texas Instruments is an excellent choice for providing the PCM1742 system clock. During the reset period (1024 system clocks), the analog outputs are forced to the bipolar zero level, or VCC/2. After the reset period, the internal register is initialized in the next 1/fS period and, if SCK, BCK, and LRCK are provided continuously, the PCM1742 provides proper analog output with unit group delay against the input data. SYSTEM CLOCK FREQUENCY (fSCLK) (MHz) SAMPLING FREQUENCY 128fS 192fS 256fS 384fS 512fS 768fS 8kHz 16kHz 32kHz 44.1kHz 48kHz 88.2kHz 96kHz 192kHz -- -- -- -- -- -- -- 24.5760 -- -- -- -- -- -- -- 36.8640 2.0480 4.0960 8.1920 11.2896 12.2880 22.5792 24.5760 See Note (1) 3.0720 6.1440 12.2880 16.9344 18.4320 33.8688 36.8640 See Note (1) 4.0960 8.1920 16.3840 22.5792 24.5760 45.1584 49.1520 See Note (1) 6.1440 12.2880 24.5760 33.8688 36.8640 See Note (1) See Note (1) See Note (1) NOTE: (1) This system clock is not supported for the given sampling frequency. TABLE I. System Clock Rates for Common Audio Sampling Frequencies. tSCKH "H" 2.0V "L" 0.8V System Clock tSCKL System clock pulse cycle time(1) System Clock Pulse Width HIGH tSCKH: 7ns (min) System Clock Pulse Width LOW tSCKL: 7ns (min) NOTE: (1) 1/256fS, 1/384fS, 1/512fS, and 1/768fS. FIGURE 1. System Clock Input Timing. 2.4V VDD 2.0V 1.6V 0V Reset Reset Removal Internal Reset Don't Care 1024 System Clocks System Clock FIGURE 2. Power-On Reset Timing. 8 PCM1742 SBAS176 AUDIO SERIAL INTERFACE The audio serial interface for the PCM1742 is comprised of a 3-wire synchronous serial port. It includes LRCK (pin 3), BCK (pin 1), and DATA (pin 2). BCK is the serial audio bit clock, and is used to clock the serial data present on DATA into the audio interface's serial shift register. Serial data is clocked into the PCM1742 on the rising edge of BCK. LRCK is the serial audio left/right word clock used to latch serial data into the serial audio interface's internal registers. Both LRCK and BCK should be synchronous to the system clock. Ideally, it is recommended that LRCK and BCK be derived from the system clock input, SCK. LRCK is operated at the sampling frequency, fS. BCK may be operated at 32, 48, or 64 times the sampling frequency (I2S format except BCK = 32fS). Internal operation of the PCM1742 is synchronized with LRCK. Accordingly, it is held when the sampling rate clock of LRCK is changed or SCK and/or BCK is broken at least for one clock cycle. If SCK, BCK, and LRCK are provided continuously after this hold condition, the internal operation will be resynchronized automatically, less than 3/fS period. In this resynchronize period, and following 3/fS, analog output is forced to the bipolar zero level, or VCC/2. External resetting is not required. AUDIO DATA FORMATS AND TIMING The PCM1742 supports industry-standard audio data formats, including Standard, I2S, and Left-Justified, as shown in Figure 3. Data formats are selected using the format bits, FMT[2:0], in Control Register 20. The default data format is 24-bit left justified. All formats require Binary Two's Complement, MSB-first audio data. See Figure 4 for a detailed timing diagram of the serial audio interface. (1) Standard Data Format: L-Channel = HIGH, R-Channel = LOW 1/fS LRCK R-Channel L-Channel BCK (= 32, 48 or 64fS) 16-Bit Right-Justified, BCK = 48fS or 64fS DATA 14 15 16 1 14 15 16 3 MSB 16-Bit Right-Justified, BCK = 32fS DATA 2 1 2 3 14 15 16 1 LSB 14 15 16 MSB 3 14 15 16 MSB 1 LSB 2 2 3 LSB 14 15 16 MSB LSB 18-Bit Right-Justified DATA 16 17 18 1 2 3 MSB 16 17 18 1 LSB 2 17 18 MSB LSB 20-Bit Right-Justified DATA 18 19 20 1 2 3 18 19 20 MSB 24-Bit Right-Justified DATA 22 23 24 1 2 1 LSB 3 22 23 24 MSB 3 18 19 20 MSB 1 LSB 2 2 LSB 3 22 23 24 MSB LSB (2) I2S Data Format: L-Channel = LOW, R-Channel = HIGH 1/fS LRCK L-Channel R-Channel BCK (= 48 or 64fS) DATA 1 2 N-2 N-1 N 3 MSB 1 LSB (3) Left-Justified Data Format: L-Channel = HIGH, R-Channel = LOW 2 N-2 N-1 N 3 MSB 1 2 1 2 LSB 1/fS L-Channel LRCK R-Channel BCK (= 32, 48 or 64fS) DATA 1 2 3 MSB N-2 N-1 N LSB 1 MSB 2 3 N-2 N-1 N LSB FIGURE 3. Audio Data Input Formats. PCM1742 SBAS176 9 LRCK 50% of VDD tBCH tBCL tLB BCK 50% of VDD tBCY tBL 50% of VDD DATA tDS SYMBOL tBCY tBCH tBCL tBL tLB tDS tDH tDH PARAMETER MIN MAX UNITS 32, 48, or 64fS(1) BCK Pulse Cycle Time BCK High Level Time BCK Low Level Time BCK Rising Edge to LRCK Edge LRCK Falling Edge to BCK Rising Edge DATA Set Up Time DATA Hold Time 35 35 10 10 10 10 ns ns ns ns ns ns NOTE: (1) fS is the sampling frequency (e.g., 44.1kHz, 48kHz, 96kHz, etc.) FIGURE 4. Audio Interface Timing. SERIAL CONTROL INTERFACE The serial control interface is a 3-wire serial port that operates asynchronously to the serial audio interface. The serial control interface is utilized to program the on-chip mode registers. The control interface includes MD (pin 13), MC (pin 14), and ML (pin 15). MD is the serial data input, used to program the mode registers, MC is the serial bit clock, used to shift data into the control port, and ML is the control port latch clock. REGISTER WRITE OPERATION All write operations for the serial control port use 16-bit data words. Figure 5 shows the control data word format. The most significant bit must be a "0". There are seven bits, labeled IDX[6:0], that set the register index (or address) for the write operation. The least significant eight bits, D[7:0], contain the data to be written to the register specified by IDX[6:0]. Figure 6 shows the functional timing diagram for writing the serial control port. ML is held at a logic "1 " state until a register needs to be written. To start the register write cycle, ML is set to logic "0". Sixteen clocks are then provided on MC, corresponding to the 16 bits of the control data word on MD. After the sixteenth clock cycle has completed, ML is set to logic "1" to latch the data into the indexed mode control register. CONTROL INTERFACE TIMING REQUIREMENTS See Figure 7 for a detailed timing diagram of the serial control interface. These timing parameters are critical for proper control port operation. MSB 0 LSB IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 D7 D6 Register Index (or Address) D5 D4 D3 D2 D1 D0 D1 D0 X Register Data FIGURE 5. Control Data Word Format for MDI. ML MC MD X 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 D7 D6 D5 D4 D3 D2 X 0 IDX6 FIGURE 6. Register Write Operation. 10 PCM1742 SBAS176 MODE CONTROL REGISTERS User-Programmable Mode Controls The PCM1742 includes a number of user-programmable functions that are accessed via control registers. The registers are programmed using the Serial Control Interface that was previously discussed in this data sheet. Table II lists the available mode control functions, along with their reset default conditions and associated register index. Register Map The mode control register map is shown in Table III. Each register includes an index (or address) indicated by the IDX[6:0] bits. tMHH 50% of VDD ML tMCH tMLS tMCL tMLH 50% of VDD MC tMCY LSB MD 50% of VDD tMDS tMCH SYMBOL tMCY tMCL tMCH tMHH tMLS tMLH tMDH tMDS PARAMETER MIN MC Pulse Cycle Time MC Low Level Time MC High Level Time ML High Level Time ML Falling Edge to MC Rising Edge ML Hold Time(1) MD Hold Time MD Set Up Time 100 50 50 Note (2) 20 20 15 20 TYP MAX UNITS ns ns ns ns ns ns ns ns 3 NOTES: (1) MC rising edge for LSB to ML rising edge. (2) 256 * f sec (min), fS = Sampling Rate. S FIGURE 7. Control Interface Timing. FUNCTION Digital Attenuation Control, 0dB to -63dB in 0.5dB Steps Soft Mute Control Oversampling Rate Control (64 or 128fS) DAC Operation Control De-Emphasis Function Control De-Emphasis Sample Rate Selection Audio Data Format Control Digital Filter Roll-Off Control Zero Flag Function Select Output Phase Select Zero Flag Polarity Select RESET DEFAULT CONTROL REGISTER INDEX, IDX[6:0] 0dB, No Attenuation Mute Disabled 64fS Oversampling DAC1 and DAC2 Enabled De-Emphasis Disabled 44.1kHz 24-Bit Left Justified Sharp Roll-Off L-/R-Channel Independent Normal Phase High 16 and 17 18 18 19 19 19 20 20 22 22 22 AT1[7:0], AT2[7:0] MUT[2:0] OVER DAC[2:1] DM12 DMF[1:0] FMT[2:0] FLT AZRO DREV ZREV TABLE II. User-Programmable Mode Controls. IDX (B8-B14) REGISTER 10H 11H 12H 13H 14H 15H 16H 16 17 18 19 20 21 22 B15 B14 B13 B12 B11 B10 B9 B8 B7 0 0 0 0 0 0 0 IDX6 IDX6 IDX6 IDX6 IDX6 IDX6 IDX6 IDX5 IDX5 IDX5 IDX5 IDX5 IDX5 IDX5 IDX4 IDX4 IDX4 IDX4 IDX4 IDX4 IDX4 IDX3 IDX3 IDX3 IDX3 IDX3 IDX3 IDX3 IDX2 IDX2 IDX2 IDX2 IDX2 IDX2 IDX2 IDX1 IDX1 IDX1 IDX1 IDX1 IDX1 IDX1 IDX0 IDX0 IDX0 IDX0 IDX0 IDX0 IDX0 AT17 AT27 RSV RSV RSV RSV RSV B6 B5 AT16 AT15 AT26 AT25 OVER RSV DMF1 DMF0 RSV FLT RSV RSV RSV RSV B4 B3 B2 B1 B0 AT14 AT24 RSV DM12 RSV RSV RSV AT13 AT23 RSV RSV RSV RSV RSV AT12 AT22 RSV RSV FMT2 RSV AZRO AT11 AT21 MUT2 DAC2 FMT1 RSV ZREV AT10 AT20 MUT1 DAC1 FMT0 RSV DREV TABLE III. Mode Control Register Map. PCM1742 SBAS176 11 REGISTER DEFINITIONS B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Register 16 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT17 AT16 AT15 AT14 AT13 AT12 AT11 AT10 Register 17 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT27 AT26 AT25 AT24 AT23 AT22 AT21 AT20 ATx[7:0] Digital Attenuation Level Setting where x = 1 or 2, corresponding to the DAC output VOUTL (x = 1) and VOUTR (x = 2). Default Value: 1111 1111B Each DAC channel (VOUTL and VOUTR) includes a digital attenuator function. The attenuation level may be set from 0dB to -63dB, in 0.5dB steps. Changes in attenuation levels are made by incrementing or decrementing, by one step (0.5dB), for every 8/fS time interval until the programmed attenuator setting is reached. Alternatively, the attenuation level may be set to infinite attenuation, or mute. The attenuation data for each channel can be set individually. The attenuation level may be set using the formula below. Attenuation Level (dB) = 0.5 (ATx[7:0]DEC - 255) where: ATx[7:0]DEC = 0 through 255 for: ATx[7:0]DEC = 0 through 128, the attenuator is set to infinite attenuation. The following table shows attenuator levels for various settings. ATx[7:0] Decimal Value Attenuator Level Setting 255 254 253 131 130 129 128 * * * 0 0dB, No Attenuation (default) -0.5dB -1.0dB -62.0dB -62.5dB -63.0dB Mute * * * Mute 1111 1111 1111 1000 1000 1000 1000 1111B 1110B 1101B 0011B 0010B 0001B 0000B * * * 0000 0000B Register 18 MUTx B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 RSV OVER RSV RSV RSV RSV B1 B0 MUT2 MUT1 Soft Mute Control Where x = 1 or 2, corresponding to the DAC output VOUTL (x = 1) and VOUTR (x = 2). Default Value: 0 MUTx = 0 MUTx = 1 Mute Disabled (default) Mute Enabled The Mute bits, MUT1 and MUT2, are used to enable or disable the Soft Mute function for the corresponding DAC outputs, VOUTL and VOUTR. The Soft Mute function is incorporated into the digital attenuators. When Mute is disabled (MUTx = 0), the attenuator and DAC operate normally. When Mute is enabled by setting MUTx = 1, the digital attenuator for the corresponding output will be decreased from the current setting to the infinite attenuation setting one attenuator step (0.5dB) at a time. This provides a "pop"-free muting of the DAC output. OVER Oversampling Rate Control Default Value: 0 OVER = 0 OVER = 1 64x Oversampling (default) 128x Oversampling The OVER bit is used to control the oversampling rate of the delta-sigma DACs. The OVER = 1 setting is recommended when the oversampling rate is 192kHz (system clock is 128 or 192fS). 12 PCM1742 SBAS176 REGISTER 19 DACx B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 RSV DMF1 DMF0 DM12 RSV RSV B1 B0 DAC2 DAC1 DAC Operation Control where x = 1 or 2, corresponding to the DAC output VOUTL (x = 1) or VOUTR (x = 2). Default Value: 0 DACx = 0 DACx = 1 DAC Operation Enabled (default) DAC Operation Disabled The DAC operation controls are used to enable and disable the DAC outputs, VOUTL and VOUTR. When DACx = 0, the corresponding output will generate the audio waveform dictated by the data present on the DATA pin. When DACx = 1, the corresponding output will be set to the bipolar zero level, or VCC/2. DM12 Digital De-Emphasis Function Control Default Value: 0 DM12 = 0 DM12 = 1 De-Emphasis Disabled (default) De-Emphasis Enabled The DM12 bit is used to enable or disable the Digital De-Emphasis function. Refer to the Typical Performance Curves of this data sheet for more information. DMF[1:0] Sampling Frequency Selection for the De-Emphasis Function Default Value: 00 DMF[1:0] 00 01 10 11 De-Emphasis Same Rate Selection 44.1kHz (default) 48kHz 32kHz Reserved The DMF[1:0] bits are used to select the sampling frequency used for the Digital De-Emphasis function when it is enabled. REGISTER 20 FMT[2:0] B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 RSV RSV FLT RSV RSV FMT2 FMT1 FMT0 Audio Interface Data Format Default Value: 101 The FMT[2:0] bits are used to select the data format for the serial audio interface. The following table shows the available format options. FMT[2:0] 000 001 010 011 100 101 110 111 PCM1742 SBAS176 Audio Data Format Selection 24-Bit Standard Format, Right-Justified Data 20-Bit Standard Format, Right-Justified Data 18-Bit Standard Format, Right-Justified Data 16-Bit Standard Format, Right-Justified Data I2S Format, 16- to 24-bits Left-Justified Format, 16- to 24-Bits (default) Reserved Reserved 13 Register 20 (Cont.) FLT Digital Filter Roll-Off Control Default Value: 0 FLT = 0 FLT = 1 Sharp Roll-Off (default) Slow Roll-Off The FLT bit allows the user to select the digital filter roll-off that is best suited to their application. Two filter roll-off selections are available: Sharp or Slow. The filter responses for these selections are shown in the Typical Performance Curves section of this data sheet. REGISTER 22 DREV B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 RSV RSV RSV RSV RSV AZRO B1 B0 ZREV DREV Output Phase Select Default Value: 0 DREV = 0 DREV = 1 Normal Output (default) Inverted Output The DREV bit is used to set the output phase of VOUTL and VOUTR. ZREV Zero Flag Polarity Select Default Value: 0 ZREV = 0 ZREV = 1 Zero Flag Pins HIGH at a Zero Detect (default) Zero Flag Pins LOW at a Zero Detect The ZREV bit allows the user to select the active polarity of Zero Flag pins. AZRO Zero Flag Function Select Default Value: 0H AZRO = 0 AZRO = 1 L-/R-Channel Independent Zero Flag (default) L-/R-Channel Common Zero Flag The AZRO bit allows the user to select the function of Zero Flag pins. AZRO = 0: Pin11: ZEROR; Zero Flag Output for R-Channel Pin12: ZEROL; Zero Flag Output for L-Channel AZRO = 1: Pin11: ZEROA; Zero Flag Output for L-/R-Channel Pin12: NA; No Assign 14 PCM1742 SBAS176 ANALOG OUTPUTS enough to attenuate the out-of-band noise to an acceptable level for many applications, therefore, an external low-pass filter is required to provide sufficient out-of-band noise rejection. Further discussion of DAC post-filter circuits is provided in the Applications Information section of this data sheet. VCOM OUTPUT The PCM1742 includes two independent output channels: VOUTL and VOUTR. These are unbalanced outputs, each capable of driving 3.1Vp-p typical into a 5k AC-coupled load. The internal output amplifiers for VOUTL and VOUTR are biased to the DC common-mode (or bipolar zero) voltage, equal to VCC/2. The output amplifiers include an RC continuous-time filter that helps to reduce the out-of-band noise energy present at the DAC outputs, due to the noise shaping characteristics of the PCM1742's delta-sigma DACs. The frequency response of this filter is shown in Figure 8. By itself, this filter is not One unbuffered common-mode voltage output pin, VCOM (pin 10), is brought out for decoupling purposes. This pin is nominally biased to a DC voltage level equal to VCC/2. This pin may be used to bias external circuits. An example of using the VCOM pin for external biasing applications is shown in Figure 9. ANALOG FILTER PERFORMANCE (100Hz-10MHz) ZERO FLAGS Zero Detect Condition 0 Zero Detection for each output channel is independent from the other. If the data for a given channel remains at a "0" level for 1024 sample periods (or LRCK clock periods), a Zero Detect condition exists for that channel. Response (dB) -10 -20 -30 -40 Zero Output Flags -50 Given that a Zero Detect condition exists for one or more channels, the Zero Flag pins for those channels will be set to a logic "1" state. There are Zero Flag pins for each channel: ZEROL (pin 12) and ZEROR (pin 11). These pins can be used -60 0.1 1 10 100 1K 10K Frequency (kHz) FIGURE 8. Output Filter Frequency Response. PCM1742 VOUTx R2 10F R1 AV = -1, where AV = - C1 R3 VCC R2 R1 2 + C2 3 1/2 OPA2353 1 Filtered Output VCOM + x = L or R 10F (a) Using VCOM to Bias a Single-Supply Filter Stage VCC PCM1742 Buffered VCOM OPA337 VCOM + 10F (b) Using a Voltage Follower to Buffer VCOM when Biasing Multiple Nodes V+ VCC 25k 49.9k 1% -IN PCM1742 VOUTx SENSE 25k OUT 25k +IN VCOM + 10F 25k To Low-Pass Filter Stage REF INA134 x = L or R V- (c) Using an INA134 for DC-Coupled Output FIGURE 9. Biasing External Circuits Using the VCOM Pin. PCM1742 SBAS176 15 to operate external mute circuits, or used as status indicators for a microcontroller, audio signal processor, or other digitally controlled functions. The active polarity of Zero Flag output can be inverted by setting the ZREV bit of Control Register 22 to "1". The reset default is active high output, or ZREV = 0. The L-channel and R-channel common Zero Flag can be selected by setting the AZRO bit of Control Register 22 to "1". The reset default is L-channel and R-channel independent Zero Flag, or AZRO = 0. APPLICATIONS INFORMATION CONNECTION DIAGRAMS A basic connection diagram is shown in Figure 11, with the necessary power-supply bypassing and decoupling components. Texas Instruments recommends using the component values shown in Figure 11 for all designs. AV - R1 C1 R3 VIN 2 3 R1 R4 1 C2 R2 VOUT OPA2134 FIGURE 10. Dual-Supply Filter Circuit. The use of series resistors (22 to 100) are recommended for the SCK, LRCK, BCK, and DATA inputs. The series resistor combines with stray PCB and device input capacitance to form a low-pass filter that reduces high-frequency noise emissions and helps to dampen glitches and ringing present on clock and data lines. PCM Audio Data Input + BCK 2 DATA ML 15 3 LRCK MC 14 4 DGND MD 13 5 VDD ZEROL/NA 12 6 VCC ZEROR/ZEROA 11 7 VOUTL 8 VOUTR System Clock SCK 16 Mode Control 10F +3.3V Regulator + 1 10F Zero Mute Control VCOM 10 + R2 POWER SUPPLIES AND GROUNDING The PCM1742 requires a +5V analog supply (VCC) and a +3.3V digital supply (VDD). The +5V supply (VCC) is used to power the DAC analog and output filter circuitry, while the +3.3V (VDD) supply is used to power the digital filter and serial interface circuitry. For best performance, the +3.3V (VDD) supply should be derived from the +5V (VCC) supply using a linear regulator, as shown in Figure 11. The REG1117-3.3 from Texas Instruments is an ideal choice for this application. Proper power-supply bypassing is shown in Figure 11. The 10F capacitors should be tantalum or aluminum electrolytic. DAC OUTPUT FILTER CIRCUITS Delta-sigma DACs utilize noise-shaping techniques to improve in-band Signal-to-Noise Ratio (SNR) performance at the expense of generating increased out-of-band noise above the Nyquist Frequency, or fS/2. The out-of-band noise must be low-pass filtered in order to provide the optimal converter performance. This is accomplished by a combination of on-chip and external low-pass filtering. Figures 9(a) and 10 show the recommended external lowpass active filter circuits for single- and dual-supply applications. These circuits are second-order Butterworth filters using a Multiple FeedBack (MFB) circuit arrangement that reduces sensitivity to passive component variations over frequency and temperature. For more information regarding MFB active filter design, please refer to Burr-Brown Applications Bulletin #34 AB-034 (SBFA001), available from our web site at http://www.ti.com. Since the overall system performance is defined by the quality of the DACs and their associated analog output circuitry, high-quality audio op amps are recommended for the active filters. The OPA2353 and OPA2134 dual op amps from Texas Instruments are recommended for use with the PCM1742, see Figures 9(a) and 10. 10F AGND 9 +5V VCC Post LPF Post LPF L-Chan OUT R-Chan OUT FIGURE 11. Basic Connection Diagram. 16 PCM1742 SBAS176 PCB LAYOUT GUIDELINES Separate power supplies are recommended for the digital and analog sections of the board. This prevents the switching noise present on the digital supply from contaminating the analog power supply and degrading the dynamic performance of the PCM1742. In cases where a common +5V supply must be used for the analog and digital sections, an inductance (RF choke, ferrite bead) should be placed between the analog and digital +5V supply connections to avoid coupling of the digital switching noise into the analog circuitry. Figure 13 shows the recommended approach for single-supply applications. A typical PCB floor plan for the PCM1742 is shown in Figure 12. A ground plane is recommended, with the analog and digital sections being isolated from one another using a split or cut in the circuit board. The PCM1742 should be oriented with the digital I/O pins facing the ground plane split/cut to allow for short, direct connections to the digital audio interface and control signals originating from the digital section of the board. Digital Power +VD Analog Power DGND AGND +5VA +VS -VS REG VCC VDD Digital Logic and Audio Processor Output Circuits DGND PCM1742 Digital Ground AGND DIGITAL SECTION Analog Ground ANALOG SECTION Return Path for Digital Signals FIGURE 12. Recommended PCB Layout. Power Supplies RF Choke or Ferrite Bead +5V AGND +VS -VS REG VCC VDD Digital Logic and Audio Processor VDD DGND Output Circuits PCM1742 AGND Common Ground DIGITAL SECTION ANALOG SECTION FIGURE 13. Single-Supply PCB Layout. PCM1742 SBAS176 17 THEORY OF OPERATION The delta-sigma section of the PCM1742 is based on an 8-level amplitude quantizer and a fourth-order noise shaper. This section converts the oversampled input data to 8-level delta-sigma format. A block diagram of the 8-level delta-sigma modulator is shown in Figure 14. This 8-level delta-sigma modulator has the advantage of stability and clock jitter sensitivity over the typical one-bit (2-level) delta-sigma modulator. The combined oversampling rate of the delta-sigma modulator and the interpolation filter is 64fS. The theoretical quantization noise performance of the 8-level delta-sigma modulator is shown in Figure 15. The enhanced multilevel delta-sigma architecture also has advantages for input clock jitter sensitivity due to the multilevel quantizer, with the simulated jitter sensitivity, as shown in Figure 16. - + 8fS Z-1 + + Z-1 Z-1 + Z-1 + + 8-Level Quantizer 64fS FIGURE 14. 8-Level Delta-Sigma Modulator. QUANTIZATION NOISE SPECTRUM (128x Oversampling) 0 0 -20 -20 -40 -40 Amplitude (dB) Amplitude (dB) QUANTIZATION NOISE SPECTRUM (64x Oversampling) -60 -80 -100 -120 -60 -80 -100 -120 -140 -140 -160 -160 -180 -180 0 1 2 3 4 5 Frequency (fS) 6 7 8 0 1 2 3 4 5 6 7 8 Frequency (fS) FIGURE 15. Quantization Noise Spectrum. 18 PCM1742 SBAS176 JITTER DEPENDENCE (64x Oversampling) 125 Dynamic Range (dB) 120 115 110 105 100 95 90 0 100 200 300 400 500 600 Jitter (ps) FIGURE 16. Jitter Sensitivity. KEY PERFORMANCE PARAMETERS AND MEASUREMENT This section provides information on how to measure key dynamic performance parameters for the PCM1742. In all cases, an Audio Precision System Two Cascade or equivalent audio measurement system is utilized to perform the testing. TOTAL HARMONIC DISTORTION + NOISE Total Harmonic Distortion + Noise (THD+N) is a significant figure of merit for audio DACs, since it takes into account both harmonic distortion and all noise sources within a specified measurement bandwidth. The true rms value of the distortion and noise is referred to as THD+N. Figure 17 shows the test setup for THD+N measurements. For the PCM1742, THD+N is measured with a full-scale, 1kHz digital sine wave as the test stimulus at the input of the DAC. The digital generator is set to a 24-bit audio word length and a sampling frequency of 44.1kHz or 96kHz. The digital generator output is taken from the unbalanced S/PDIF connector of the measurement system. The S/PDIF data is transmitted via a coaxial cable to the digital audio receiver on the DEM-DAI1742 demo board. The receiver is then configured to output 24-bit data in either I2S or leftjustified data format. The DAC audio interface format is programmed to match the receiver output format. The analog output is then taken from the DAC post filter and connected to the analog analyzer input of the measurement system. The analog input is band limited using filters resident in the analyzer. The resulting THD+N is measured by the analyzer and displayed by the measurement system. Evaluation Board DEM-DAI1742 S/PDIF Receiver PCM1742 2nd-Order Low-Pass Filter f-3dB = 54kHz or 108kHz S/PDIF Output Digital Generator Analyzer and Display 0dBFS, 1kHz Sine Wave rms Mode 20kHz Apogee Filter Band Limit HPF = 22Hz LPF = 30kHz Notch Filter fC = 1kHz FIGURE 17. Test Setup for THD+N Measurements. PCM1742 SBAS176 19 DYNAMIC RANGE Dynamic range is specified as A-Weighted, THD+N measured with a -60dBFS, 1kHz digital sine wave stimulus at the input of the DAC. This measurement is designed to give a good indicator of how the DAC will perform given a low-level input signal. The measurement setup for the dynamic range measurement is shown in Figure 18, and is similar to the THD+N test setup discussed previously. The differences include the band limit filter selection, the additional A-Weighting filter, and the -60dBFS input level. IDLE CHANNEL SIGNAL-TO-NOISE RATIO The SNR test provides a measure of the noise floor of the DAC. The input to the DAC is all "0"s data, and the DAC's Infinite Zero Detect Mute function must be disabled (default condition at power up for the PCM1742). This ensures that the delta-sigma modulator output is connected to the output amplifier circuit so that idle tones (if present) can be observed and effect the SNR measurement. The dither function of the digital generator must also be disabled to ensure an all "0"s data stream at the input of the DAC. The measurement setup for SNR is identical to that used for dynamic range, with the exception of the input signal level (see the notes provided in Figure 18). Evaluation Board DEM-DAI1742 PCM1742(1) S/PDIF Receiver 2nd-Order Low-Pass Filter f-3dB = 54kHz S/PDIF Output Digital Generator Analyzer and Display 0% Full-Scale, Dither Off (SNR) -60dBFS, 1kHz Sine Wave (Dynamic Range) rms Mode A-Weight Filter(1) Band Limit HPF = 22Hz LPF = 22kHz Option = A-Weighting(2) Notch Filter fC = 1kHz NOTES: (1) Infinite Zero Detect Mute disabled. (2) Results without A-Weighting will be approximately 3dB worse. FIGURE 18. Test Setup for Dynamic Range and SNR Measurements. 20 PCM1742 SBAS176 PACKAGE OPTION ADDENDUM www.ti.com 3-Oct-2003 PACKAGING INFORMATION ORDERABLE DEVICE STATUS(1) PACKAGE TYPE PACKAGE DRAWING PINS PACKAGE QTY PCM1742E ACTIVE SSOP DBQ 16 98 PCM1742E/2K ACTIVE SSOP DBQ 16 2000 PCM1742KE ACTIVE SSOP DBQ 16 98 PCM1742KE/2K ACTIVE SSOP DBQ 16 2000 (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. IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI's terms and conditions of sale supplied at the time of order acknowledgment. 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