The PCM1748 is a CMOS, monolithic, integrated circuit which includes stereo digital-to-analog converters (DAC) and support circuitry in a small SSOP-16 package

PCM1748

Manufacturer Part NumberPCM1748
DescriptionThe PCM1748 is a CMOS, monolithic, integrated circuit which includes stereo digital-to-analog converters (DAC) and support circuitry in a small SSOP-16 package
ManufacturerTexas Instruments
PCM1748 datasheet
 


Specifications of PCM1748

# Dacs2# Inputs / # Outputs0 / 2
ArchitectureDelta-SigmaResolution(bits)24
Sampling Rate(max)(khz)96Control InterfaceSPI
Digital Audio InterfaceL,R,I2SThd+n(typ)(%)0.002
Dac Snr(typ)(db)100Power Consumption(typ)(mw)62
Analog Voltage Av/dd(min)(v)4.5Analog Voltage Av/dd(max)(v)5.5
Pin/package16SSOP/QSOP  
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24-Bit, 96-kHz Sampling, Enhanced Multilevel, Delta-Sigma,
FEATURES
24-Bit Resolution
Analog Performance (V
= 5 V):
CC
– Dynamic Range:
106 dB, Typical (PCM1748KE)
100 dB, Typical (PCM1748E)
– SNR:
106 dB, Typical (PCM1748KE)
100 dB, Typical (PCM1748E)
– THD+N:
0.002%, Typical (PCM1748KE)
0.003%, Typical (PCM1748E)
– Full-Scale Output: 3.1 Vp-p, Typical
8× Oversampling Digital Filter:
– Stop-Band Attenuation: –55 dB
– Pass-Band Ripple: ±0.03 dB
Sampling Frequency: 5 kHz to 100 kHz
System Clock: 256 f
, 384 f
S
S
With Autodetect
Accepts 16-, 18-, 20-, and 24-Bit Audio Data
2
Data Formats: Standard, I
S, and
Left-Justified
User-Programmable Mode Controls:
– Digital Attenuation: 0 dB to –63 dB,
0.5 dB/Step
– Digital De-Emphasis
– Digital Filter Rolloff: Sharp or Slow
– Soft Mute
– Zero Flags for Each Output
Dual-Supply Operation:
– 5-V Analog
– 3.3-V Digital
5-V Tolerant Digital Inputs
Small SSOP-16 Package
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.
FilterPro is a trademark of Texas Instruments.
System Two, Audio Precision are trademarks of Audio Precision, Inc.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Audio Digital-to-Analog Converter
APPLICATIONS
AV Receivers
DVD Movie Players
DVD Add-On Cards for High-End PCs
HDTV Receivers
Car Audio Systems
Other Applications Requiring 24-Bit Audio
DESCRIPTION
The PCM1748 is a CMOS, monolithic, integrated
circuit which includes stereo digital-to-analog con-
verters (DAC) and support circuitry in a small
SSOP-16 package. The data converters use Texas
Instruments' enhanced multilevel delta-sigma archi-
tecture that employs fourth-order noise shaping and
8-level amplitude quantization to achieve excellent
dynamic performance and improved tolerance to
clock jitter. The PCM1748 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 100 kHz are supported. A full
, 512 f
, 768 f
S
S
set of user-programmable functions is accessible
through a 3-wire serial-control port that supports
register write functions.
PCM1748
SBAS165B – MAY 2001 – REVISED APRIL 2005
Copyright © 2001–2005, Texas Instruments Incorporated

PCM1748 Summary of contents

  • Page 1

    ... HDTV Receivers Car Audio Systems Other Applications Requiring 24-Bit Audio DESCRIPTION The PCM1748 is a CMOS, monolithic, integrated circuit which includes stereo digital-to-analog con- verters (DAC) and support circuitry in a small SSOP-16 package. The data converters use Texas Instruments' enhanced multilevel delta-sigma archi- ...

  • Page 2

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) Power supply voltage Power supply voltage Supply voltage difference Ground voltage differences Digital input voltage Input current (except power supply) ...

  • Page 3

    ... S A-weighted kHz 44.1 kHz kHz –90 dB OUT bipolar zero OUT CC PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 , and 24-bit data, unless otherwise S MIN TYP MAX UNIT 10 –10 65 100 –10 2.4 VDC 1 VDC 0.003% 0.008% 0.004% 1 ...

  • Page 4

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 ELECTRICAL CHARACTERISTICS (continued) All specifications 25° noted PARAMETER ANALOG OUTPUT Output voltage Center voltage Load impedance DIGITAL FILTER PERFORMANCE Filter Characteristics, Sharp Rolloff Pass band Pass band Stop band ...

  • Page 5

    ... Enhanced Oversampling Multilevel Digital Filter Delta− Sigma with Modulator Function Controller DAC Zero Detect PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 Output Amp and V L OUT Low− Pass F ilter V COM Output Amp and Low− Pass F ilter ...

  • Page 6

    ... OUT ZEROL/NA 12 ZEROR/ZEROA 11 (1) Schmitt-trigger input, 5-V tolerant (2) Schmitt-trigger input with internal pulldown, 5-V tolerant 6 PIN ASSIGNMENTS 1 16 BCK SCK DATA LRCK DGND PCM1748 ZEROL/ ZEROR/ZEROA OUT AGND OUT TERMINAL FUNCTIONS I/O DESCRIPTION – ...

  • Page 7

    ... S TRANSITION CHARACTERISTICS (SLOW ROLLOFF − 1 − 2 − 3 − 4 − SBAS165B – MAY 2001 – REVISED APRIL 2005 , and 24-bit input data, unless S 0 0.1 0.2 0.3 0.4 Frequency ( Figure 2. 0.1 0.2 0.3 0.4 Frequency ( Figure 4. PCM1748 0.5 0.5 7 ...

  • Page 8

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 TYPICAL PERFORMANCE CURVES (continued) All specifications 25° Digital Filter (De-Emphasis Curves) DE-EMPHASIS (f S 0.0 − 1.0 − 2.0 − 3.0 − 4.0 − 5.0 − 6.0 − 7.0 − 8.0 − 9.0 − 10 Frequency (kHz) Figure 5. DE-EMPHASIS (f S 0.0 − 1.0 − ...

  • Page 9

    ... S 106 S 104 102 S 100 5 110 108 106 104 102 100 PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 DYNAMIC RANGE 3 44.1kHz, 384f S 96kHz, 384f S 4 (V) CC Figure 12. CHANNEL SEPARATION 3.3 V) ...

  • Page 10

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 TYPICAL PERFORMANCE CURVES (continued) ANALOG DYNAMIC PERFORMANCE (continued) All specifications 25° Temperature Characteristics TOTAL HARMONIC DISTORTION + NOISE vs TEMPERATURE (T 10 − 60dB/96kHz, 384f 1 − 60dB/44.1kHz, 384f 0.1 0.01 0dB/96kHz, 384f ...

  • Page 11

    ... SYSTEM CLOCK AND RESET FUNCTIONS SYSTEM CLOCK INPUT The PCM1748 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). frequencies for common audio sampling rates. Figure 19 shows the timing requirements for the system clock input. For optimal performance important to use a clock source with low phase jitter and noise ...

  • Page 12

    ... 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 serial shift register. Serial data is clocked into the PCM1748 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 internal registers ...

  • Page 13

    ... AUDIO DATA FORMATS AND TIMING The PCM1748 supports industry-standard audio data formats, including standard Figure 21. 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 2s complement, MSB-first audio data. See detailed timing diagram of the serial audio interface. (1) Sta nd ard D ata Fo rm at: L − ...

  • Page 14

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 LRCK t BCH BCK t DATA SYMBOL t BCK pulse cycle time BCY t BCK high-level time BCH t BCK low-level time BCL t BCK rising edge to LRCK edge BL t LRCK falling edge to BCK rising edge LB t DATA setup time ...

  • Page 15

    ... IDX6 IDX 5 IDX 4 IDX3 IDX 2 IDX1 IDX0 IDX 4 IDX3 IDX 2 IDX 1 IDX0 Register Data Figure 24. Register Write Operation PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 Figure 23 shows the control data word LSB ...

  • Page 16

    ... S MODE CONTROL REGISTERS User-Programmable Mode Controls The PCM1748 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 2 lists the available mode control functions, along with their reset default conditions and associated register index ...

  • Page 17

    ... AT14 AT13 AT12 AT26 AT25 AT24 AT23 AT22 2). OUT ATTENUATOR LEVEL SETTING 0 dB, no attenuation (default) –0.5 dB – –62 dB –62.5 dB –63 dB Mute : Mute PCM1748 B1 B0 AT11 AT10 AT21 AT20 MUT2 MUT1 DAC2 DAC1 FMT1 FMT0 RSV (1) RSV (1) ZREV DREV B1 B0 AT11 ...

  • Page 18

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 B15 B14 B13 B12 REGISTER 18 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 MUTx – Soft Mute Control where corresponding to the DAC output V Default value: 0 MUTx = 0 Mute disabled (default) MUTx = 1 ...

  • Page 19

    ... The DMF[1:0] bits select the sampling frequency used for the digital de-emphasis function when it is enabled. B11 B10 RSV DMF1 OUT OUT PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 DMF0 DM12 RSV RSV DAC2 ...

  • Page 20

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 B15 B14 B13 B12 REGISTER 20 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 FMT[2:0] – 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 ...

  • Page 21

    ... L and V R. OUT OUT Pin 11: ZEROR = zero-flag output for R-channel Pin 12: ZEROL = zero flag output for L-channel Pin 11: ZEROA = zero flag output for L-/R-channel Pin 12: NA, not assigned PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 RSV RSV ...

  • Page 22

    ... OUT 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 PCM1748 delta-sigma DACs. The frequency response of this filter is shown in 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 ...

  • Page 23

    ... V+ CC 25k 49.9k 1% 25k −IN 25k + 25k INA134 − V SBAS165B – MAY 2001 – REVISED APRIL 2005 Figure 27 −1, where A − 1/2 Filtered OP A2353 Output V COM SENSE OUT To Low− Pass Filter Stage REF Pin COM PCM1748 23 ...

  • Page 24

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 ZERO FLAGS Zero-Detect Condition Zero detection for each output channel is independent from the other. If the data for a given channel remains level for 1024 sample periods (or LRCK clock periods), a zero-detect condition exists for that channel. ...

  • Page 25

    ... Power Supplies and Grounding The PCM1748 requires a 5-V analog supply (V power the DAC analog and output filter circuitry, while the 3.3-V supply is used to power the digital filter and serial interface circuitry. For best performance, the 3.3-V supply should be derived from the 5-V supply using a ...

  • Page 26

    ... A typical PCB floor plan for the PCM1748 is shown in analog and digital sections being isolated from one another using a split or cut in the circuit board. The PCM1748 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 ...

  • Page 27

    ... Processor DIGITAL SECTION THEORY OF OPERATION The delta-sigma section of the PCM1748 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 stability and clock jitter sensitivity over the typical one-bit (2-level) delta-sigma modulator. The combined ...

  • Page 28

    ... PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 APPLICATION INFORMATION (continued) QUANTIZATION NOISE SPECTRUM (64x Oversampling) 0 − 20 − 40 − 60 − 80 − 100 − 120 − 140 − 160 − 180 Frequency ( − 20 − 40 − 60 − 80 − 100 − ...

  • Page 29

    ... THD+N. measurements. For the PCM1748, THD+N is measured with a full-scale, 1-kHz 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 44.1 kHz or 96 kHz. The digital generator output is taken from the unbalanced S/PDIF connector of the measurement system ...

  • Page 30

    ... The SNR test provides a measure of the noise floor of the DAC. The input to the DAC is all-0s data, and the DAC infinite-zero-detect mute function must be disabled (default condition at power up for the PCM1748). 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 affect the SNR measurement ...

  • Page 31

    ... V capacitor. In Figure 30 and Figure Figure 31, changed leftmost block to Digital Logic and Audio Processor. Corrected parameters in test setup diagram, PCM1748 SBAS165B – MAY 2001 – REVISED APRIL 2005 DESCRIPTION < format and condition for synchronization availability S Figure 22, Audio Interface Timing, period ...

  • Page 32

    ... PCM1748E/2KG4 ACTIVE SSOP/QSOP PCM1748EG/2K ACTIVE SSOP/QSOP PCM1748EG4 ACTIVE SSOP/QSOP PCM1748KE ACTIVE SSOP/QSOP PCM1748KE/2K ACTIVE SSOP/QSOP PCM1748KE/2KG4 ACTIVE SSOP/QSOP PCM1748KEG4 ACTIVE SSOP/QSOP (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. ...

  • Page 33

    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 ...

  • Page 34

    ... TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Type Drawing PCM1748E/2K SSOP/ DBQ QSOP PCM1748KE/2K SSOP/ DBQ QSOP PACKAGE MATERIALS INFORMATION Pins SPQ Reel Reel A0 (mm) Diameter Width (mm) W1 (mm) 16 2000 330.0 12.4 6.4 16 2000 330.0 12.4 6.4 Pack Materials-Page 1 ...

  • Page 35

    ... Device Package Type PCM1748E/2K SSOP/QSOP PCM1748KE/2K SSOP/QSOP PACKAGE MATERIALS INFORMATION Package Drawing Pins SPQ Length (mm) DBQ 16 2000 DBQ 16 2000 Pack Materials-Page 2 11-Mar-2008 Width (mm) Height (mm) 346.0 346.0 29.0 346.0 346.0 29.0 ...

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  • Page 38

    ... 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’ ...