a
FEATURES
5 V Stereo Audio DAC System
Accepts 16-/18-/20-/24-Bit Data
Supports 24 Bits and 96 kHz Sample Rate
Multibit Sigma-Delta Modulator with 鈥淧erfect Differen-
tial Linearity Restoration鈥?for Reduced Idle Tones
and Noise Floor
Data Directed Scrambling DAC鈥擫east Sensitive to
Jitter
Differential Output for Optimum Performance
113 dB Signal-to-Noise and Dynamic Range at 48 kHz
Sample Rate
110 dB Signal-to-Noise and Dynamic Range at 96 kHz
Sample Rate
鈥?7 dB THD+N
On-Chip Volume Control with 1024 Steps
Hardware and Software Controllable Clickless Mute
Zero Input Flag Outputs for Left and Right Channels
Digital De-Emphasis Processing
Supports 128, 256, 384, and 512 F
S
Master Mode
Clock
Switchable Clock Doubler
Power-Down Mode Plus Soft Power-Down Mode
Flexible Serial Data Port with Right-Justified, Left-
Justified, I
2
S-Compatible and DSP Serial Port Modes
28-Lead SSOP Plastic Package
APPLICATIONS
DVD, CD, Set-Top Boxes, Home Theater Systems, Auto-
motive Audio Systems, Computer Multimedia Prod-
ucts, Sampling Musical Keyboards, Digital Mixing
Consoles, Digital Audio Effects Processors
Stereo, 96 kHz, Multibit
DAC
AD1855*
PRODUCT OVERVIEW
The AD1855 is a high performance, single-chip stereo, audio
DAC delivering 113 dB Dynamic Range and SNR (A-weighted鈥?/div>
not muted) at 48 kHz sample rate. It is comprised of a multibit
sigma-delta modulator with dither, continuous time analog
filters and analog output drive circuitry. Other features include
an on-chip stereo attenuator and mute, programmed through an
SPI-compatible serial control port. The AD1855 is fully com-
patible with current DVD formats, including 96 kHz sample
frequency and 24 bits. It is also backwards compatible by sup-
porting 50
碌s/15 碌s
digital de-emphasis intended for 鈥渞edbook鈥?/div>
44.1 kHz sample frequency playback from compact discs.
The AD1855 has a very 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 converters.
The AD1855 can be configured in left-justified, I
2
S, right-
justified, or DSP serial port compatible modes. The AD1855
accepts 16-/18-/20-/24-bit serial audio data in MSB first, twos-
complement format. A power-down mode is offered to mini-
mize power consumption when the device is inactive. The
AD1855 operates from a single +5 V power supply. It is fabri-
cated on a single monolithic integrated circuit and housed in a
28-lead SSOP package for operation over the temperature range
0擄C to +70擄C.
FUNCTIONAL BLOCK DIAGRAM
CONTROL DATA
INPUT
VOLUME
MUTE
3
96/48F
S
DIGITAL CLOCK
CLOCK
IN
SUPPLY
2
384/256
X2MCLK
AD1855
SERIAL CONTROL
INTERFACE
8
INTERPOLATOR
8
INTERPOLATOR
VOLTAGE
REFERENCE
CLOCK
CIRCUIT
16-/18-/20-/24-BIT 3
DIGITAL
DATA INPUT
SERIAL 2
MODE
SERIAL
DATA
INTERFACE
ATTEN/
MUTE
ATTEN/
MUTE
MULTIBIT SIGMA-
DELTA MODULATOR
MULTIBIT SIGMA-
DELTA MODULATOR
DAC
OUTPUT
BUFFER
OUTPUT
BUFFER
ANALOG
OUTPUTS
DAC
2
PD/RST
MUTE
DE-EMPHASIS
ANALOG
SUPPLY
2
ZERO
FLAG
*Patents
Pending.
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
漏 Analog Devices, Inc., 2000
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