REV. 0
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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.
a
Serial-Port 16-Bit
SoundPort Stereo Codec
AD1849K
FEATURES
Single-Chip Integrated
SD
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 and TQFP Packages
Operation from +5 V and Mixed +5 V/+3.3 V Supplies
Serial Interface Compatible with ADSP-21xx Fixed-
Point DS
m
Ps
Compatible with CS4215 (See Text)
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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.
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.
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.
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 (mono)
speaker.
(Continued on page 8)
FUNCTIONAL BLOCK DIAGRAM
MUX
ANALOG
IN
CRYSTALS
ANALOG
SUPPLY
DIGITAL
SUPPLY
POWER DOWN
LINE L
LINE R
MIC L
MIC R
L
R
GAIN
OSCILLATORS
REFERENCE
2.25V
MUTE
∑∆
A/D
CONVERTER
∑∆
A/D
CONVERTER
GAIN
2
2
LINE 0 L
LINE 1 L
HEADPHONE RETURN
ANALOG
OUT
∑
∑
MONITOR MIX
ATTENUATE
∑
∑∆
D/A
CONVERTER
∑∆
D/A
CONVERTER
INTERPOL
INTERPOL
ATTENUATE
CHAINING
INPUT
CHAINING
OUTPUT
OUT
RETURN
MONO SPEAKER
ATTENUATE
ATTENUATE
ANALOG
FILTER
ANALOG
FILTER
LOOPBACK
L
R
20
dB
LINE 0 R
LINE 1 R
S
E
R
I
A
L
P
O
R
T
L
O
O
P
B
A
C
K
DATA/CONTROL
MODE
DATA/CONTROL
TRANSMIT
2
RESET
DATA/CONTROL
RECEIVE
PARALLEL I/O
BIT CLOCK
FRAME SYNC
DIGITAL
I/O
AD1849K
µ
/A
LAW
µ
/A
LAW
µ
/A
LAW
µ
/A
LAW
MUTE
L
R
MUTE
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 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
SoundPort is a registered trademark of Analog Devices, Inc.
