Cirrus Logic CS6422 - Manual

Preliminary Product Information
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
1
Copyright  Cirrus Logic, Inc. 2001
(All Rights Reserved)
P.O. Box 17847, Austin, Texas 78760
(512) 445 7222 FAX: (512) 445 7581
http://www.cirrus.com
CS6422
Enhanced Full-Duplex Speakerphone IC
Features
l Single-chip
, full-duplex, hands-free operation
l Optional Tx Noise Guard
l Programmable attenuation during double-talk
l Optional 34 dB microphone preamplifier
l Dual channel AGC’ed volume controls with
mute
l Dual integrated 80 dB IDR codecs
l Speech-trained Network and Acoustic Echo
Cancellers
l Rx and Tx supplementary echo suppression
l Configurable half-duplex training mode
l Powerdown mode
l Microcontroller Interface
General Description
Most modern speakerphones use half-duplex operation,
which alternates transmission between the far-end talker
and the speakerphone user. This is done to ensure sta-
bility because the acoustic coupling between the
speaker and microphone is much higher in speaker-
phones than in handsets where the coupling is
mechanically suppressed.
The CS6422 enables full-duplex conversation using
echo cancellation and suppression in a single-chip solu-
tion. The CS6422 can easily replace existing half-duplex
speakerphone ICs with a huge increase in conversation
quality.
The CS6422 consists of telephone & audio interfaces,
two codecs and an echo-cancelling DSP.
ORDERING INFORMATION
See page 48 .
CS6422-IS -40
o
to 85
o
C 20-pin SOIC
CDB6422 Evaluation Board
TGain
TVol
Σ
+
-
Acoustic
Echo
Canceller
ADC
Pre-emphasis
Filter
+
ASdt
DAC Σ
+
-
Network
Echo
Canceller
Pre-emphasis
Filter
+
NSdt
DAC
ADC
Clock
Generation
Voltage
Reference
Microcontroller Interface
RGain RVol
(0, 6, 9.5, 12 dB)
Network
Sidetone
(none, -24,
-18, -12 dB)
Acoustic
Sidetone
(none, -24,
-18, -12 dB)
1 k Ω
Mic
34 dB
(0, 6, 9.5, 12 dB)
NI
NO
17
4
8 7 6 5 15 2 19
18
APO
API
20
CLKO
13
14
CLKI
AO
3
AVDD DVDD NC1 NC2 NC3 NC4
9 10 11 12 16 1
(Mute, -12 to +30 dB)
(Mute, -12 to +30 dB)
Rx
Suppression
Tx
Suppression
JUL ‘01
DS295PP4
Copyright
© Cirrus Logic, Inc. 2005
(All Rights Reserved)
http://www.cirrus.com
CS6422
Enhanced Full-duplex Speakerphone IC
SEP ‘05
DS295F1