TS34118

1-20

2004/09 rev. B

TS34118

Voice Switched Speakerphone Circuit

SOP-28

DIP-28

Supply Voltage Range -1.0 V to 7.0V

Microphone Amplifier, & Hybrid Amplifier

Gain 40 dB

General Description

The TS34118 Voice Switched Speakerphone Circuit incorporates the necessary amplifiers, attenuators, level detectors,

and control algorithm to form the heart of a high quality hands-free speakerphone system. Included are a microphone

amplifier with adjustable gain and MUTE control, Transmit and Receive attenuators which operate in a complementary

manner, level detectors at both input and output of both attenuators, and background noise monitors for both the transmit

and receive channels. A Dial Tone Detector prevents the dial being attenuated by the Receive background noise monitor

circuit. Also included are two line drive amplifiers which can be used to form a hybrid network in conjunction with an

external coupling transformer. A high-pass filter can be used to filter out 60Hz noise in the receive channel, or for other

filtering functions .A Chip Disable pin permits powering down the entire circuit to conserve power on long loops where

loop current is at a minimum.

The TS34118 may be operated from a power supply, or it can be powered from the telephone line, requiring typically

5.0mA. The TS34118 can be interfaced directly to Tip and Ring (through a coupling transformer) for stand-alone

operation, or it can be used in conjunction with a handset speech network and/or other features of a feature phone

Features

Improved attenuator gain range: 52dB between

transmit and receive.

Low voltage operation for line-powered applications

(3.0-6.5V).

4-point signal sensing for improved sensitivity.

Back ground noise monitors for both transmit

and receive paths.

Standard 28-pin plastic DIP package and SOP

package available.

Microphone amplifier gain set by external

resistors-mute function included.

Chip disable for active/standby operation.

On board filter pinned-out for user defined function.

Dial tone detector to inhibit receive idle mode during

dial tone presence.

Compatible with TS34119 speaker amplifier.

Ordering Information

Part No.

Operating Temp.

Package

TS34118CD

DIP-28

TS34118CS

-20 ~ +70

SOP-28

Absolute Maximum Rating

Description

Value

Unit

Supply voltage (pin 4)

-1.0, +7.0

V

Voltage at CD (pin 3), MUT (pin 12)

-1.0,Vcc +1.0

V

Voltage at VLC (pin 13)

-1.0,Vcc +0.5

V

Voltage at TXI (pin 9),RXI (pin 21),FI(pin 2)

-0.5,Vcc +0.5

V

Storage temperature range

-65 to +150