DTMF receiver for telephones
Communication ICs
DTMF receiver for telephones
BU8872 / BU8872FS
The BU8872 and BU8872FS are DTMF receiver ICs develope...
Description
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 microcomputer. 4) Input pins equipped with hysteresis. (ACK pin) FBlock diagram
5) 4.19MHz ceramic resonator or crystal resonator can be used. 6) 8-pin DIP package. (BU8872) 16-pin SSOP package. (BU8872FS)
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Communication ICs
FAbsolute maximum ratings (Ta=25_C)
BU8872 / BU8872FS
FRecommended operating conditions (Ta=25_C)
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Communication ICs
FElectrical characteristics DC characteristics (unless otherwise noted, Ta=25_C, VDD=5.0V)
BU8872 / BU8872FS
AC characteristics (unless otherwise noted, Ta=25_C, VDD=5.0V)
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Communication ICs
FPin descriptions
BU8872 / BU8872FS
FInput / output circuits
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Communication ICs
FCircuit operation A DTMF signal is supplied to the INPUT pin and applied to a pair of 6th-order bandpass filters, which separa...
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