Serial-Port 16-Bit
®
a
SoundPort Stereo Codec
AD1849K
FEATURES
(mono) speaker and stereo headphone drive circuits that require
no additional external components. Dynamic range exceeds
80 dB over the 20 kHz audio band. Sample rates from 5.5 kHz
to 48 kHz are supported from external crystals, from an external
clock, or from the serial interface bit clock.
Single-Chip Integrated ⌺⌬ Digital Audio Stereo Codec
Multiple Channels of Stereo Input and Output
Digital Signal Mixing
On-Chip Speaker and Headphone Drive Capability
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 Package
The Codec includes a stereo pair of Σ∆ analog-to-digital converters
and a stereo pair of Σ∆ digital-to-analog converters. Analog signals
can be input at line levels or microphone levels. 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.
Operation from 5 V and Mixed 5 V/3.3 V Supplies
Serial Interface Compatible with ADSP-21xx Fixed-
Point DSPs
The left and right channel 16-bit outputs from the ADCs are
available over a single bidirectional serial interface that also sup-
ports 16-bit digital input to the DACs and control information.
The AD1849K can accept and generate 8-bit µ-law or A-law
companded digital data.
Compatible with CS4215 (See Text)
PRODUCT OVERVIEW
The Serial-Port AD1849K SoundPort Stereo Codec integrates
the key audio data conversion and control functions into a single
integrated circuit. The AD1849K is intended to provide a com-
plete, single-chip audio solution for multimedia applications
requiring operation from a single 5 V supply. External signal
path circuit requirements are limited to three low tolerance
capacitors for line level applications; anti-imaging filters are
incorporated on-chip. The AD1849K includes on-chip monaural
The Σ∆ DACs are preceded by a digital interpolation filter. An
attenuator provides independent user volume control over each
DAC channel. Nyquist images and shaped quantization noise
are removed from the DACs’ analog stereo output by on-chip
switched-capacitor and continuous-time filters. Two independent
stereo pairs of line-level (or one line-level and one headphone)
outputs are generated, as well as drive for a monaural speaker.
FUNCTIONAL BLOCK DIAGRAM
DIGITAL
SUPPLY
ANALOG
SUPPLY
CRYSTALS
POWER-DOWN
2
2
DIGITAL
I/O
LINE L
LINE R
OSCILLATORS
L
DATA/CONTROL
MODE
⌺⌬ A/D
/A
ANALOG
IN
GAIN
GAIN
CONVERTER
LAW
MIC L
MIC R
20
DATA/CONTROL
TRANSMIT
MUX
dB
R
S
⌺⌬ A/D
CONVERTER
/A
LAW
E
R
I
L
O
O
P
B
A
C
K
LOOPBACK
A
L
MONITOR MIX
P
O
R
T
L
⌺⌬ D/A
CONVERTER
ANALOG
FILTER
/A
LAW
ATTENUATE
ATTENUATE
⌺
INTERPOL ATTENUATE
LINE 0 L
MUTE
MUTE
DATA/CONTROL
RECEIVE
R
L
⌺⌬ D/A
CONVERTER
ANALOG
FILTER
/A
LAW
LINE 0 R
LINE 1 L
INTERPOL ATTENUATE
⌺
2
PARALLEL I/O
BIT CLOCK
FRAME SYNC
ANALOG
OUT
⌺
MUTE
HEADPHONE RETURN
LINE 1 R
R
AD1849K
REFERENCE
RESET
OUT
RETURN
MONO SPEAKER
CHAINING CHAINING
OUTPUT INPUT
2.25V
SoundPort is a registered trademark of Analog Devices, Inc.
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
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
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2000