Serial-Port 16-Bit
SoundPort Stereo Codec
a
AD1849K
FEATURES
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
Program m able Gain and Attenuation
On-Chip Signal Filters
T he 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. T he
ADCs’ output can be digitally mixed with the DACs’ input.
Digital Interpolation and Decim ation
Analog Output Low -Pass
Sam ple 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 Com patible w ith ADSP-21xx Fixed-
Point DSPs
T he 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.
T he AD1849K can accept and generate 8-bit µ-law or A-law
companded digital data.
Com patible w ith CS4215 (See Text)
P RO D UCT O VERVIEW
T he Serial-Port AD1849K SoundPort® Stereo Codec integrates
the key audio data conversion and control functions into a single
integrated circuit. T he 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
T he 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.
SoundPort is a registered trademark of Analog Devices, Inc.
(Continued on page 8)
FUNCTIO NAL BLO CK D IAGRAM
DIGITAL
SUPPLY
ANALOG
SUPPLY
CRYSTALS
POWER DOWN
2
2
DIGITAL
I/O
LINE L
LINE R
OSCILLATORS
L
DATA/CONTROL
MODE
∑∆ A/D
µ/A
ANALOG
OUT
GAIN
GAIN
CONVERTER
LAW
MIC L
MIC R
20
DATA/CONTROL
TRANSMIT
MUX
dB
R
S
∑∆ A/D
CONVERTER
µ/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
µ/A
LAW
∑
ATTENUATE
ATTENUATE
INTERPOL ATTENUATE
LINE 0 L
MUTE
MUTE
DATA/CONTROL
RECEIVE
R
L
∑∆ D/A
CONVERTER
ANALOG
FILTER
µ/A
LAW
LINE 0 R
LINE 1 L
∑
INTERPOL ATTENUATE
2
PARALLEL I/O
BIT CLOCK
ANALOG
IN
FRAME SYNC
∑
MUTE
HEADPHONE RETURN
LINE 1 R
R
AD1849K
REFERENCE
RESET
OUT
RETURN
MONO SPEAKER
CHAINING CHAINING
OUTPUT INPUT
2.25V
REV. 0
Inform ation furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assum ed by Analog Devices for its
use, nor for any infringem ents of patents or other rights of third parties
which m ay result from its use. No license is granted by im plication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norw ood, MA 02062-9106, U.S.A.
Tel: 617/ 329-4700 Fax: 617/ 326-8703