U4090B Datasheet, PDF (1/34 Pages) TEMIC Semiconductors – Monolithic Integrated Feature Phone Circuit

Monolithic Integrated Feature Phone Circuit
U4090B
Description
The µc controlled telephone circuit U4090B 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
amplification of signals and adaptation to the line.
An integrated voice switch with loudspeaker amplifier
allows loudhearing or handsfree 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 DC characteristic adjustable
D Transmit and receive gain adjustable
D Symmetrical input of microphone amplifier
D Anti-clipping in transmit direction
D Automatic line loss compensation
D Symmetrical output of earpiece amplifier
D Built-in ear protection
D DTMF and MUTE input
D Adjustable sidetone suppression independent
of sending and receiving amplification
D Speech circuit with two sidetone networks
D Built-in line detection circuit
D Integrated amplifier for loudhearing operation
D Anti-clipping for loudspeaker amplifier
D Improved acoustical feedback suppression
D Power down
D Voice switch
D Tone ringer interface with dc/dc converter
D Zero crossing detection
D Common speaker for loudhearing and tone ringer
D Supply voltages for all functional blocks of a
subscriber set
D Integrated transistor for short circuiting the line
voltage
D Answering machine interface
D Operation possible from 10 mA line currents
Benefits
D Savings of one piezo electric transducer
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
Speech
circuit
Voice
switch
Audio
amplifier
Tone
ringer
Loudhearing
and
Tone ringing
MC with
EEPROM/
DTMF
94 8741
TELEFUNKEN Semiconductors
1 (34)
Rev. C1, 28-Oct-96
Preliminary Information