U4089B Datasheet, PDF (1/25 Pages) ATMEL Corporation – MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT

Features
• Adjustable DC Characteristics
• Adjustable Transmit and Receive Gain
• Symmetrical Input of Microphone Amplifier
• Anti-clipping in Transmit Direction
• Automatic Line-loss Compensation
• Built-in Ear Protection
• DTMF and MUTE Input
• Adjustable Side Tone Suppression Independent of Sending and Receiving
Amplification
• Integrated Amplifier for Loud-hearing Operation
• Anti-clipping for Loudspeaker Amplifier
• Improved Acoustical Feedback Suppression
• Selectable Line Impedance
• Voice Switch
• Supply Voltages for All Functional Blocks of a Subscriber Set
• Operation Possible from 10-mA Line Current
Benefits
• Complete System Integration of Analog Signal Processing on One Chip
• Very Few External Components
Monolithic
Integrated
Feature Phone
Circuit
U4089B-M
Applications
• Feature Phones
• Answering Machines
• Fax Machines
• Speaker Phones
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
Rev. 4570A–CORD–04/03
1