U4090B-P Datasheet, PDF (2/35 Pages) ATMEL Corporation – Monolithic Integrated Feature Phone Circuit EMI Improved

1. Description
The microcontroller-controlled telephone circuit U4090B-P 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 cir-
cuit is line powered and contains all components necessary for amplification of signals and
adaptation to the line.
An integrated voice switch with loudspeaker amplifier allows loud-hearing or hands-free opera-
tion. 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 1-1. Block Diagram
Speech
circuit
Audio
amplifier
Loudhearing
and
Tone ringing
Voice
switch
Tone
ringer
MC with
EEPROM/
DTMF
2 U4090B-P
4741C–CORD–11/05