The MC145740 has been discontinued. Suggested replacement: none.
The MC145740 is a silicon gate HCMOS LSI designed for general purpose Dual Tone Multiple Frequency (DTMF) communications,
and contains a DTMF signal generator and a receiver for all 16 standard digits.
The generator block has a differential line driver which drives a 600 ohm load with 0 dBm level. The transmit signal level
is adjusted in 1 dB steps by the programmable attenuator.
The receiver block has an Auto Gain Control (AGC) amplifier to demodulate 50 dB (typ) dynamic range of DTMF signals to the
The device also includes a serial control interface that permits a CPU to exercise several built-in features.