ROHM BU8874F, BU8874 Datasheet
Communication ICs
DTMF receiver for telephones
BU8874 / BU8874F
The BU8874 and BU8874F 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 (BU8874) 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 microcontroller.
Applications
Telephone answering machines
Features
1) Dynamic range of 45dB. (internal AGC)
2) Power down mode.
3) 4-bit binary serial data output.
4) Guard time can be controlled through host microcontroller.
5) Input pins equipped with hysteresis. (ACK pin)
Block diagram
6) 4.19MHz crystal resonator can be used.
7) 8-pin DIP package. (BU8874)
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Communication ICs BU8874 / BU8874F
FAbsolute maximum ratings (Ta=25_C)
FRecommended operating conditions (Ta=25_C)
FPin descriptions
203
Communication ICs BU8874 / BU8874F
Input / output circuits
INPUT PWDN
OSC ACK
SD ESt
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