BU8871F Rohm, BU8871F Datasheet
BU8871F
Related parts for BU8871F
BU8871F Summary of contents
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... DTMF receiver for telephones BU8871F The BU8871F is a DTMF receiver ICs developed for use in telephone answering machines, and converts 16 different types of DTMF signals into 4-bit binary serial data. It features 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 ...
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... Communication ICs FAbsolute maximum ratings (Ta=25_C) FRecommended operating conditions (Ta=25_C) FPin descriptions BU8871F 181 ...
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... Communication ICs FInput / output circuits 182 BU8871F ...
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... Communication ICs FElectrical characteristics DC characteristics (unless otherwise noted, Ta=25_C characteristics (unless otherwise noted, Ta=25_C, V =5.0V) DD =5.0V) DD BU8871F 183 ...
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... Communication ICs FMeasurement circuits 184 BU8871F ...
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... DTMF input cannot be de- coded properly. Any ACK pulses in excess of four are ig- nored until ESt goes HIGH again. Table 1 shows the format of serial data output from the SD pin. (2) Overall timing chart (3) ACK and SD timing BU8871F 185 ...
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... Communication ICs FCircuit operation (4) Serial data correspondence table FApplication example 186 BU8871F ...
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... If you are injecting an external clock, X501 should be omitted and DC blocking capacitor C591 used in its place. Typically, this capacitor should be 47nF. JP592 : If DTMF signals are being input directly, both ends should be shorted. Q591 Use these to increase the sensitivity of R591 X R595 the DTMF receiver. C592, C593 BU8871F 187 ...
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... Also external clock is being injected blocking capacitor must be inserted. Select a capacitor that will neither attenuate the frequency components or put an excessive load on the drive side. BU8871F ...
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... 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 BU8871F 189 ...
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... Communication ICs FApplication board patterns 190 BU8871F ...
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... Communication ICs FExternal dimensions (Units: mm) BU8871F 191 ...