73M223

73M223 1200 Baud FSK Modem February 1998 DESCRIPTION The 73M223 modem device receives and transmits serial and binary data over existing telephone networks using Frequency Shift Keying (FSK). It provides the filtering, modulation, and demodulation to implement a serial, asynchronous data communication channel. The 73M223 employs the CCITT V.23 signaling frequencies of 1302 and 2097 Hz, operating at 1200 baud, and is intended for half duplex operation over a two-line system. The 73M223 provides a cost-effective alternative to existing modem solutions. It is ideally suited for R.F. data links, credit verification systems, point-of-sale terminals, and remote process control. CMOS technology ensures small size, low-power consumption and enhanced reliability. FEATURES Low cost FSK Modem 1200 baud operation CMOS switched capacitor technology Built-in self-test feature On-chip filtering, and Modulation/Demodulation Uses CCITT V.23 frequencies On chip crystal oscillator Low power/High reliability Does not require a microprocessor 10 mW @ 5 V supply 16-pin plastic packages BLOCK DIAGRAM TXD OSC1 13 14 OSC2 12 7; 7 TEST PHASE COHERENT WAVE SYNTHESIZER 7(67 OSC PROGRAMMABLE DIGITAL DIVIDER DIGITAL TIMING SIGNALS 16 TXA 15 SYNC PHASE LOCKED LOOP 9 CLK SYNC 15 6<1 7(67 RXA FIL 2 5 TEST DIGITAL DEMODULATOR SLICER DELAY DIGITAL LP FILTER TEST 7(67 11 RXD RXF 4 SWITCHED CAP BANDPASS FILTER RANDOM SEQUENCE GENERATOR 6 TEST 3 CAP 1 VDD 8 VSS 73M2...