AD1857_15 Datasheet, PDF (1/16 Pages) Analog Devices – Stereo, Single Supply 16-, 18- and 20-Bit Sigma-Delta DACs

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Stereo, Single Supply
16-, 18- and 20-Bit Sigma-Delta DACs
AD1857/AD1858
FEATURES
Low Cost, High Performance Stereo DACs
128 Times Oversampling Interpolation Filter
Multibit ⌺⌬ Modulator with Triangular PDF Dither
Discrete Time and Continuous Time Analog
Reconstruction Filters
Extremely Low Out-of-Band Energy
Buffered Outputs with 2 k⍀ Output Load Drive
94 dB Dynamic Range, –90 dB THD+N Performance
Digital De-emphasis and Mute
؎0.1؇C Maximum Phase Linearity Deviation
Continuously Variable Sample Rate Support
Power-Down Mode
16-, 18- and 20-Bit I²S-Justified, Left-Justified Modes
Offered on AD1857
Accepts 24-Bit Word
16-Bit Right-Justified and DSP Serial Port Modes
Offered on AD1858
Single +5 V Supply
20-Pin SSOP Package
APPLICATIONS
Digital Cable TV and Direct Broadcast Satellite Set-Top
Decoder Boxes
Video Laser Disk, Video CD and CD-I Players
High Definition Televisions, Digital Audio Broadcast
Receivers
CD, CD-R, DAT, DCC and MD Players
Digital Audio Workstations, Computer Multimedia
Products
PRODUCT OVERVIEW
The AD1857/AD1858 are complete single-chip stereo digital
audio playback components. They each comprise an advanced
digital interpolation filter, a revolutionary “linearity-compensated”
multibit sigma-delta (∑∆) modulator with dither, a jitter-tolerant
DAC, switched capacitor and continuous time analog filters and
analog output drive circuitry. Other features include digital
de-emphasis processing and mute. The AD1857/AD1858
support continuously variable sample rates with essentially
linear phase response, and support 50/15 µs digital de-emphasis
intended for “Redbook” 44.1 kHz sample frequency playback
from Compact Discs. The user must provide a master clock that
is synchronous with the left/right clock at 256 or 384 times the
intended sample frequency.
The AD1857/AD1858 have a simple but very flexible serial data
input port that allows for glueless interconnection to a variety of
ADCs, DSP chips, AES/EBU receivers and sample rate con-
verters. The AD1857 serial data input port can be configured
in either 16-bit, 18-bit or 20-bit left-justified or I²S-justified
modes. The AD1858 serial data input port can be configured in
either 16-bit right-justified or DSP serial port compatible modes.
The AD1857/AD1858 accept serial audio data in MSB first,
twos-complement format. A power-down mode is offered to
minimize power consumption when the device is inactive. The
AD1857/AD1858 operate from a single +5 V power supply.
They are fabricated on a single monolithic integrated circuit and
housed in 20-pin SSOP packages for operation over the
temperature range 0°C to +70°C.
DIGITAL
SUPPLY
2
FUNCTIONAL BLOCK DIAGRAM
COMMON
MODE
CLOCK CLOCK
MODE
IN
16-/18-/20-BIT
DIGITAL ³
DATA INPUT
SERIAL DATA
INTERFACE
AD1857/AD1858
VOLTAGE
REFERENCE
CLOCK
CIRCUIT
SERIAL
MODE
128x
INTERPOLATION
FILTER
128x
INTERPOLATION
FILTER
MUTE
MUTE
MULTIBIT
Σ∆ MODULATOR
MULTIBIT
Σ∆ MODULATOR
DAC
DAC
ANALOG
FILTER
ANALOG
FILTER
OUTPUT
BUFFER
OUTPUT
BUFFER
ANALOG
OUTPUTS
DE-EMPHASIS
MUTE
POWER-DOWN/RESET
4
ANALOG
SUPPLY
REV. 0
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© Analog Devices, Inc., 1997