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
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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
TDK [ TDK ELECTRONICS ]
