CS6420 Datasheet, PDF (1/52 Pages) Cirrus Logic – FULL DUPLEX SPEAKERPHONE CHIP

CS6420
Full-Duplex Speakerphone Chip
Features
l Single-chip full-duplex hands-free operation
l Automatic gain control
l Optional 34 dB microphone preamplifier
l Integrated mute and volume control
l Integrated 80 dB IDR dual codec
l Speech-trained Network and Acoustic Echo
Cancellers
l Powerdown mode
l Microcontroller Interface
General Description
Most modern speakerphones use half-duplex operation,
which switches transmission between the far-end talker
and the speakerphone user. This is done because the
acoustic coupling between the speaker and microphone
is much higher in speakerphones than in handsets
where the coupling is mechanically suppressed.
The CS6420 enables full-duplex conversation with a sin-
gle-chip solution. The CS6420 can easily replace
existing half-duplex speakerphone ICs with a huge in-
crease in conversation quality.
The CS6420 consists of telephone & audio interfaces,
two codecs and an echo-cancelling DSP.
ORDERING INFORMATION
CS6420-CS
CDB6420
20-pin SOIC
Evaluation Board
DGND
NC4
NC3 NC2
NC1
AGND
AVDD
NI
0,6,9.5,12 dB
Pre-Emphasis
Filter
+_Σ
-
Network
Echo Canceller
Acoustic
Echo Canceller
Pre-Emphasis
Filter
AO
Clock
Generation
CLKI
CLKO
NO
DVDD
-
Σ₊
Microcontroller Interface
DATA STROBE DRDY
RST
1 kΩ
34 dB API
0,6,9.5,12 dB
2.12 V
BANDGAP
3.5 V
AVDD
APO
MB
Preliminary Product Information
Cirrus Logic, Inc.
Crystal Semiconductor Products Division
P.O. Box 17847, Austin, Texas 78760
[phone] FAX: [phone]
http://www.crystal.com
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
Copyright © Cirrus Logic, Inc. 1997
(All Rights Reserved)
JUN ‘97
DS205PP2
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