High Performance Multibit ꢀ-ꢁ DAC
a
with SACD Playback
AD1955
FEATURES
FUNCTIONAL BLOCK DIAGRAM
5 V Power Supply Stereo Audio DAC System
Accepts 16-/18-/20-/24-Bit Data
Supports 24-Bit, 192 kHz Sample Rate PCM Audio Data
Supports SACD Bit Stream and External Digital Filter
Interface
DSD
BITSTREAM
INPUT
MASTER
CLOCK INPUT
CONTROL
DATA INPUT
3
4
DIGITAL
SUPPLY
Accepts a Wide Range of PCM Sample Rates Including:
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, and
192 kHz
Multibit Sigma-Delta Modulator with "Perfect Differen-
tial Linearity Restoration" for Reduced Idle Tones and
Noise Floor
AUTO-CLOCK
DIVIDER
SPI CONTROL
16-/20-/24-BIT
AUDIO DATA/
EXTERNAL
DIGITAL
3/4
MUX
DSD FILTER
FILTER INPUT
Data Directed Scrambling DAC––Low Sensitivity to Jitter
Supports SACD Playback with "Bit Expansion" Filter
Differential Current Output for Optimum Performance
8.64 mA p-p Differential Output
120 dB SNR/DNR (not muted) at 48 kHz Sample Rate
(A-Weighted Stereo)
SERIAL DATA
INTERFACE
EXTERNAL
FILTER I/F
RESET
MUTE
DIGITAL
FILTER ENGINE
S/H
ANALOG
SUPPLY
123 dB SNR/DNR (Mono)
–110 dB THD + N
110 dB Stop-Band Attenuation with ꢂ0.0002 dB
Pass-Band Ripple
ZERO
FLAGS
NOISE-SHAPED
SCRAMBLING
MULTIBIT ꢀ-ꢁ
MODULATOR
8ꢃ Oversampling Digital Filter
On-Chip Clickless Volume Control
VOLTAGE
REFERENCE
I-DAC
I-DAC
Supports SACD-Mute Pattern Detection
Supports 64 fS/128 fS DSD SACD with Phase Mode
Internal Digital Filter Pass-Through for External Filter
Master Clock: 256 fS, 512 fS, 768 fS
Hardware and Software Controllable Clickless Mute
Serial (SPI) Control for Serial Mode, Number of Bits,
Sample Rate, Volume, Mute, De-Emphasis, Mono Mode
Digital De-Emphasis for 32 kHz, 44.1 kHz, and 48 kHz
Sample Rates
L-CH
DIFFERENTIAL
CURRENT OUTPUT
R-CH
PRODUCT OVERVIEW
The AD1955 is a complete, high performance, single-chip, stereo
digital audio playback system. It is comprised of a multibit sigma-
delta modulator, high performance digital interpolation filters,
and continuous-time differential current output DACs. Other
features include an on-chip clickless stereo attenuator and mute
capability, programmed through an SPI compatible serial control
port. The AD1955 is fully compatible with all known DVD audio
formats including 192 kHz as well as 96 kHz sample frequencies
and 24 bits. It is also backward compatible by supporting 50 µs/
15 µs digital de-emphasis intended for “redbook” compact discs,
as well as de-emphasis at 32 kHz and 48 kHz sample rates.
Flexible Serial Data Port with Right-Justified, Left-
Justified, I2S, and DSP Modes
28-Lead SSOP Plastic Package
APPLICATIONS
High End DVD Audio
SACD
CD
Home Theater Systems
Automotive Audio Systems
Sampling Musical Keyboards
Digital Mixing Consoles
Digital Audio Effects Processors
The AD1955 has a very flexible serial data input port that
allows for glueless interconnection to a variety of ADCs, DSPs,
SACD decoders, external digital filters, AES/EBU receivers, and
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REV. 0
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reliable. However, no responsibility is assumed by Analog Devices for its
use, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 2002