1

Features

Amplification

Benefits

Applications

Description

The telephone circuit U4089B-M is a linear integrated circuit for use in feature phones,

answering machines and fax machines. It contains the speech circuit, side tone

equivalent and ear protection rectifiers. The circuit is line-powered and contains all

components necessary for the amplification of signals and adaptation to the line.

An integrated voice switch with a loudspeaker amplifier enables loud-hearing or

hands-free operation. With an anti-feedback function, acoustical feedback during loud-

hearing can be reduced significantly. The generated supply voltage is suitable for a

wide range of peripheral circuits.

Figure 1. Simple Block Diagram

Speech

circuit

Audio

amplifier

Voice

switch

Dialer

Monolithic

Integrated

Feature Phone

Circuit

U4089B-M

Rev. 4570A–CORD–04/03