cf8223a Nippon Precision Circuits Inc, (NPC), cf8223a Datasheet - Page 12

• Manufacturer Part Number: cf8223a
• Description: Fsk Decoder And Dtmf Receiver Ic
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

The DTMF receiver determines whether the received
data (DTMF signal) is valid after an interval of
t
LOW and data is output on DOUT. If DTMF data is
not detected after an interval t
pause is activated and the next DTMF signal is in a
REC
≥ 40ms stable reception. If valid, DV goes
DTMF signal
DOUT
SPA
Figure 5. DTMF signal to DOUT output
≥ 20ms, a data
DTMF DATA
Start bit
0
CF8223A
Q
0
DTMF data
(LSB first)
Q
wait state (see timing diagrams in AC Electrical
Characteristics). The CF8223A DTMF receiver can
be used as a general-purpose DTMF receiver without
the need for the external time constant circuit, in
which case the resistor/capacitor/diode network can
be omitted.
1
Q
2
Q
3
S
0
(LSB first)
Checksum
(2'mod16)
S
1
NIPPON PRECISION CIRCUITS INC.—12
S
2
S
3
Stop bit
1