危鈭?/div>
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鈥?output can be digitally mixed with the DACs鈥?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
碌-law
or A-law
companded digital data.
The
危鈭?/div>
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鈥?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)
The Serial-Port AD1849K SoundPort廬 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
SoundPort is a registered trademark of Analog Devices, Inc.
FUNCTIONAL BLOCK DIAGRAM
ANALOG
SUPPLY
DIGITAL
SUPPLY
CRYSTALS
2
2
POWER DOWN
DIGITAL
I/O
LINE L
LINE R
OSCILLATORS
L
GAIN
MIC L
MIC R
20
dB
MUX
R
GAIN
LOOPBACK
ANALOG
OUT
鈭戔垎
A/D
CONVERTER
碌/A
LAW
S
E
R
I
A
L
P
O
R
T
DATA/CONTROL
MODE
DATA/CONTROL
TRANSMIT
L
O
O
P
B
A
C
K
DATA/CONTROL
RECEIVE
PARALLEL I/O
BIT CLOCK
FRAME SYNC
RESET
鈭戔垎
A/D
CONVERTER
碌/A
LAW
MONITOR MIX
L
LINE 0 L
MUTE
LINE 0 R
R
L
LINE 1 L
MUTE R
ANALOG
FILTER
ANALOG
FILTER
ATTENUATE
鈭戔垎
D/A
CONVERTER
鈭戔垎
D/A
CONVERTER
INTERPOL
ATTENUATE
鈭?/div>
鈭?/div>
碌/A
LAW
碌/A
LAW
ATTENUATE
INTERPOL
ATTENUATE
2
ANALOG
IN
HEADPHONE RETURN
LINE 1 R
鈭?/div>
MUTE
REFERENCE
OUT
RETURN
2.25V
AD1849K
MONO SPEAKER
CHAINING
OUTPUT
CHAINING
INPUT
REV. 0
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: 617/329-4700
Fax: 617/326-8703
next