The MT8888 is a monolithic DTMF transceiver with call progress filter. It is fabricated in CMOS technology offering low power consumption and high reliability. The receiver section is based upon the industry standard MT8870 DTMF receiver while the transmitter utilizes a switched capacitor D/A converter for low distortion, high accuracy DTMF signalling. Internal counters provide a burst mode such that tone bursts can be transmitted with precise timing. A call progress filter can be selected allowing a microprocessor to analyze call progress tones. The MT8888CS1 utilizes an Intel micro interface, which allows the device to be connected to a number of popular microcontrollers with minimal external logic.Product Cross Reference: When replacing the California Micro Devices CM8888 or the Clare M8888 with the MT8888C, RD, WR Rise and Fall time tR, tF need to be changed from 25 ns to 20 ns maximum. The Address Hold Time tAH needs to be increased from 10 ns to 26 ns minimum. Similarly, RD to Valid Data Delay tDDR needs to be shortened from 150 ns to 100 ns maximum.It is also recommended to add a 4.7 Mohm resistor between Pin OSC1 to VSS to ensure that the crystal oscillator will start up properly.Typical ApplicationsCredit card systemsPaging systemsRepeater systems/mobile radioInterconnect dialersPersonal computers

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