SoundPort Stereo Codec
Single-Chip Integrated ⌺⌬ Digital Audio Stereo Codec
Supports the Microsoft Windows Sound System*
Multiple Channels of Stereo Input
Analog and Digital Signal Mixing
Programmable Gain and Attenuation
On-Chip Signal Filters
Digital Interpolation and Decimation
Analog Output Low-Pass
Sample Rates from 5.5 kHz to 48 kHz
44-Lead PLCC and TQFP Packages
Operation from +5 V Supplies
Serial Digital Interface Compatible with ADSP-21xx
The AD1847 SoundPort® Stereo Codec integrates key audio
data conversion and control functions into a single integrated
circuit. The AD1847 is intended to provide a complete, low
cost, single-chip solution for business, game audio and multi-
media applications requiring operation from a single +5 V sup-
ply. It provides a serial interface for implementation on a
computer motherboard, add-in or PCMCIA card. See Figure 1
for an example system diagram.
*Windows Sound System is a registered trademark of Microsoft Corp.
SoundPort is a registered trademark of Analog Devices, Inc.
Figure 1. Example System Diagram
External circuit requirements are limited to a minimal number
of low cost support components. Anti-imaging DAC output
filters are incorporated on-chip. Dynamic range exceeds 70 dB
over the 20 kHz audio band. Sample rates from 5.5 kHz to
48 kHz are supported from external crystals.
The Codec includes a stereo pair of ∑∆ analog-to-digital con-
verters (ADCs) and a stereo pair of ∑∆ digital-to-analog con-
verters (DACs). Inputs to the ADC can be selected from four
stereo pairs of analog signals: line 1, line 2, auxiliary (“aux”)
line #1, and post-mixed DAC output. A software-controlled
programmable gain stage allows independent gain for each
channel going into the ADC. The ADCs’ output can be digitally
mixed with the DACs’ input.
The pair of 16-bit outputs from the ADCs is available over a se-
rial interface that also supports 16-bit digital input to the DACs
and control/status information. The AD1847 can accept and
generate 16-bit twos-complement PCM linear digital data, 8-bit
unsigned magnitude PCM linear data, and 8-bit µ-law or A-law
companded digital data.
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FUNCTIONAL BLOCK DIAGRAM
ANALOG ANALOG DIGITAL
I/O SUPPLY SUPPLY
LINE 1 L
LINE 2 L
AUX 1 L
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which may result from its use. No license is granted by implication or
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® Analog Devices, Inc., 1996
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