SigmaDSP
™
3-Channel, 26-Bit
Signal Processing DAC
AD1954
FEATURES
5 V 3-Channel Audio DAC System
Accepts Sample Rates up to 48 kHz
7 Biquad Filter Sections per Channel
Dual Dynamic Processor with Arbitrary Input/Output Curve
and Adjustable Time Constants
0 ms to 6 ms Variable Delay/Channel for Speaker Alignment
Stereo Spreading Algorithm for Phat Stereo™ Effect
Program RAM Allows Complete New Program Download
via SPI Port
Parameter RAM Allows Complete Control of More Than
200 Parameters via SPI Port
SPI Port Features Safe-Upload Mode for Transparent Filter
Updates
2 Control Registers Allow Complete Control of Modes and
Memory Transfers
Differential Output for Optimum Performance
112 dB Signal-to-Noise (Not Muted) at 48 kHz Sample Rate
(A-Weighted Stereo)
70 dB Stop-Band Attenuation
On-Chip Clickless Volume Control
Hardware and Software Controllable Clickless Mute
Digital De-emphasis Processing for 32 kHz, 44.1 kHz, and
48 kHz Sample Rates
Flexible Serial Data Port with Right-Justified, Left-Justified,
I
2
S Compatible, and DSP Serial Port Modes
Auxiliary Digital Input
Graphical Custom Programming Tools
44-Lead MQFP or 48-Lead LQFP Plastic Package
APPLICATIONS
2.0/2.1 Channel Audio Systems (Two Main Channels plus
Subwoofer)
Multimedia Audio
Automotive Sound Systems
Minicomponent Stereo
Home Theater Systems (AC-3 Postprocessor)
Musical Instruments
In-Seat Sound Systems (Aircraft, Motor Coaches)
GENERAL DESCRIPTION
The AD1954 is a complete 26-bit single-chip 3-channel digital
audio playback system with built-in DSP functionality for speaker
equalization, dual-band compression/limiting, delay compensa-
tion, and image enhancement. These algorithms can be used to
compensate for real-world limitations of speakers, amplifiers, and
listening environments, resulting in a dramatic improvement of
perceived audio quality.
The signal processing used in the AD1954 is comparable to that
found in high-end studio equipment. Most of the processing is
done in full 48-bit double-precision mode, resulting in very good
low-level signal performance and the absence of limit cycles or
idle tones. The compressor/limiter uses a sophisticated two-band
algorithm often found in high-end broadcast compressors.
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on 9)
FUNCTIONAL BLOCK DIAGRAM
SERIAL DATA
OUTPUT
3
3
3
3
MASTER CLOCK
OUTPUT
MCLK
GENERATOR
(256f
S
/512f
S
)
AUDIO DATA
MUX
26
22
DSP CORE
DATA FORMAT:
3.23 (SINGLE PRECISION)
3.45 (DOUBLE PRECISION)
DAC – L
AD1954
SERIAL DATA
INPUTS
DAC – R
ANALOG
OUTPUTS
MASTER
CLOCK INPUTS
MCLK
MUX
DAC – SW
AUX SERIAL
DATA INPUT
SPI DATA
OUTPUT
SPI INPUT
3
SERIAL CONTROL
INTERFACE
RAM
ROM
DATA CAPTURE
OUT
DIGITAL
OUTPUT
REV. A
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
that may result from its use. No license is granted by implication or other-
wise under any patent or patent rights of Analog Devices.Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P Box 9106, Norwood, MA 02062-9106, U.S.A.
.O.
Tel: 781/329-4700
Fax: 781/326-8703
© 2003 Analog Devices, Inc. All rights reserved.
AD [ ANALOG DEVICES ]
