BU8871F Datasheet, PDF (10/12 Pages) Rohm – DTMF receiver for telephones

Communication ICs
BU8871F
This LSI is not equipped with the power-on reset function. Also, since the internal circuit (flip-flop circuit) becomes unsta-
ble at the rising edge of the power supply, the internal circuit is initialized as shown below by the first DTMF sequence
received after the rising edge of the power supply. Therefore, input four dummy ACK pulses before the DTMF reception.
FElectrical characteristic curves
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