BU8872 Rohm Semiconductor, BU8872 Datasheet
BU8872
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BU8872 Summary of contents
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... 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 ...
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... Communication ICs FAbsolute maximum ratings (Ta=25_C) FRecommended operating conditions (Ta=25_C) BU8872 / BU8872FS 193 ...
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... Communication ICs FElectrical characteristics DC characteristics (unless otherwise noted, Ta=25_C characteristics (unless otherwise noted, Ta=25_C, V 194 BU8872 / BU8872FS =5.0V) DD =5.0V) DD ...
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... Communication ICs FPin descriptions FInput / output circuits BU8872 / BU8872FS 195 ...
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... If the pulse sequence input to the ACK pin consists of three or fewer pulses, the next 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. 196 BU8872 / BU8872FS ...
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... Communication ICs Table 1. Serial data correspondence table FApplication example BU8872 / BU8872FS 197 ...
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... JP501 : This is normally shorted. To test the current con- sumption of the IC, insert a DC ammeter in place of JP501. (2) Oscillation components 198 BU8872 / BU8872FS X501, C551, and C552 : Use a crystal or ceramic resona- tor with an oscillation frequency of 4.194304MHz. If using a ceramic resonator, there may be problems with the precision of the oscillation frequency recommend using one of the ceramic resonators listed below ...
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... The ESt guard time is determined by the CPU of the host computer, but to reduce the load on the host computer, the guard time can be set using an external circuit, as shown below. BU8872 / BU8872FS The relation between a momentary falter in the ESt guard time ( momentary HIGH level in the ESt guard time ...
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... Communication ICs FElectrical characteristic curves 200 BU8872 / BU8872FS ...
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... Communication ICs FExternal dimensions (Units: mm) BU8872 / BU8872FS 201 ...