U4091BM
Programmable Telephone Audio Processor
Description
The programmable telephone audio processor U4091BM
is a linear integrated circuit for use in feature phones,
answering machines and fax machines. It contains the
speech circuit, tone-ringer interface with DC/DC
converter, sidetone equivalent and ear-protection
rectifiers. The circuit is line-powered and contains all
components necessary for signal amplification and
adaptation to the line. The U4091BM can also be supplied
via an external power supply. An integrated voice switch
with loudspeaker amplifier enables hands-free or
loudhearing operation. With an anti-feedback function,
acoustical feedback during loudhearing can be reduced
significantly. The generated supply voltage is suitable for
a wide range of peripheral circuits.
Features
D
Speech circuit with anti-clipping
D
Tone-ringer interface with DC/DC converter
D
Speaker amplifier with anti-distortion
D
Power-supply management (regulated, unregulated)
and a special supply for electret microphone
D
Voice switch
D
Interface for answering machine and cordless phone
Benefits
D
No piezoelectric transducer for tone ringing necessary
D
Complete system integration of analog signal proces-
sing on one chip
D
Very few external components
Applications
Feature phone, answering machine, fax machine, speaker
phone, cordless phone
Block Diagram
Speech
circuit
Voice
switch
Audio
amplifier
Clock
Data
Reset
Serial
bus
DTMF
Tone
ringer
MCU
Ordering Information
Extended Type Number
U4091BM-MFN
U4091BM-MFNG3
Package
SSO44
SSO44
Taped and reeled
Remarks
Rev. A3, 27-Oct-00
1 (32)