CF8223A datasheet(13/15 Pages) NPC

Part #	CF8223A

Description	FSK Decoder and DTMF Receiver IC

PDF	15 Pages

Scroll/Zoom	100%

Manufacturer	NPC [Nippon Precision Circuits Inc]

Direct Link	http://www.npc.co.jp/en

Logo

13 / 15 page

SM8223A

NIPPON PRECISION CIRCUITS—13

The DTMF receiver determines whether the received

data (DTMF signal) is valid after an interval of

tREC ≥ 40ms stable reception. If valid, DV goes

LOW and data is output on DOUT. If DTMF data is

not detected after an interval tSPA ≥ 20ms, a data

pause is activated and the next DTMF signal is in a

wait state (see timing diagrams in AC Electrical

Characteristics). The SM8223A 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.

Figure 5. DTMF signal to DOUT output

DTMF signal

DOUT

Stop bit

DTMF DATA

Start bit

DTMF data

(LSB first)

Checksum

(2'mod16)

(LSB first)

CF8223A Datasheet(PDF) 13 Page - Nippon Precision Circuits Inc