TLH5004

October 1991

TP5088 DTMF Generator for Binary Data

General Description

This CMOS device provides low cost tone-dialing capability

in microprocessor-controlled telephone applications 4-bit

binary data is decoded directly without the need for conver-

sion to simulated keyboard inputs required by standard

DTMF generators With the TONE ENABLE input low the

oscillator is inhibited and the device is in a low power idle

mode On the low-to-high transition of TONE ENABLE data

is latched into the device and the selected tone pair from

the standard DTMF frequencies is generated An open-drain

N-channel transistor provides a MUTE output during tone

generation

Features

Y

Direct microprocessor interface

Y

Binary data inputs with latches

Y

Generates 16 standard tone pairs

Y

On-chip 3579545 MHz crystal-controlled oscillator

Y

Better than 064% frequency accuracy

Y

High group pre-emphasis

Y

Low harmonic distortion

Y

MUTE output interfaces to speech network

Y

Low power idle mode

Y

35V – 8V operation

Block Diagram

TLH5004 – 1

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A