Part #

Description

M-8870-01

18-pin plastic DIP

M-8870-01SM

18-pin plastic SOIC

M-8870-01SMTR

18-pin plastic SOIC, tape and reel

M-8870-02

18-pin plastic DIP, power-down,

option

M-8870-02SM

18-pin plastic SOIC, power-down,

option

M-8870-02T

18-pin plastic SOIC, power-down

option, tape and reel

www.clare.com

DS-M8870-R3

M-8870

DTMF Receiver

1

Block Diagram

Pin Configuration

Ordering Information

Features

Applications

Description

The M-8870 is a full DTMF Receiver that integrates

both bandsplit filter and decoder functions into a single

18-pin DIP or SOIC package. Manufactured using

CMOS process technology, the M-8870 offers low

power consumption (35 mW max) and precise data

handling. Its filter section uses switched capacitor

technology for both the high and low group filters and

for dial tone rejection. Its decoder uses digital counting

techniques to detect and decode all 16 DTMF tone

pairs into a 4-bit code. External component count is

minimized by provision of an on-chip differential input

amplifier, clock generator, and latched tri-state inter-

face bus. Minimal external components required

include a low-cost 3.579545 MHz color burst crystal, a

timing resistor, and a timing capacitor.

The M-8870-02 provides a “power-down” option

which, when enabled, drops consumption to less

than 0.5 mW. The M-8870-02 can also inhibit the

decoding of fourth column digits (see Tone Decoding

table on page 5).