192

Communication ICs

DTMF receiver for telephones

BU8872 / BU8872FS

The BU8872 and BU8872FS are DTMF receiver ICs developed for use in telephone answering machines, and convert

16 different types of DTMF signals into 4-bit binary serial data. In addition to a compact 8-pin DIP (BU8872) or 16-pin

SSOP (BU8872FS) package, these receivers feature a wide dynamic range, eliminating the need for an external input

amplifier. Expertise from a number of companies has been incorporated into these products to enable guard time control

through a host microcomputer.

FApplications

Telephone answering machines

FFeatures

1) Dynamic range of 45dB. (internal AGC)

2) 4-bit binary serial data output.

3) Guard time can be controlled through host micro-

computer.

4) Input pins equipped with hysteresis. (ACK pin)

5) 4.19MHz ceramic resonator or crystal resonator can

be used.

6) 8-pin DIP package. (BU8872)

16-pin SSOP package. (BU8872FS)

FBlock diagram