4-245

Description

The CD22202 and CD22203 complete dual-tone multiple

frequency (DTMF) receivers detect a selectable group of 12

or 16 standard digits. No front-end pre-filtering is needed.

The only externally required components are an inexpensive

3.579545MHz TV “colorburst’’ crystal (for frequency refer-

ence) and a bias resistor. Extremely high system density is

possible through the use of the clock output of a crystal con-

nected CD22202/CD22203 receiver to drive the time bases

of additional receivers. This is a monolithic integrated circuit

fabricated with low-power, complementary symmetry CMOS

processing. It only requires a single low tolerance power

supply.

The CD22202 and CD22203 employ state-of-the-art circuit

technology to combine the digital and analog functions on

the same CMOS chip using a standard digital semiconductor

process. The analog input is preprocessed by 60Hz reject

and band splitting filters and then hard limited to provide

AGC. Eight Bandpass filters detect the individual tones. The

digital post processor times the tone durations and provides

the correctly coded digital outputs. Outputs interface directly

to standard CMOS circuitry and are three-state enabled to

facilitate bus oriented architectures.

January 1997

Pinout

CD22202, CD22203

(PDIP)

TOP VIEW

D1

EN

IN1633

XEN

ANALOG IN

10

11

12

13

14

15

16

17

18

9

8

7

6

5

4

3

2

1

D2

D4

D8

CLRDV

DV

ATB

XIN

XOUT

HEX/B28

ED (203 ONLY),

NC (202)

Functional Diagram

HIGH B/P

FILTERS

LOW B/P

FILTERS

VOLTAGE

REG./REF.

CHIP

CLOCKS

ATB

XEN

INI633

13

8

12

11

510

7

4

6

15

14

2

1

18

17

16

3

CLRDV

DV

D1

D2

D4

D8

EN

XIN

XOUT

HEX/B28

ED-203

NC-202

ANALOG IN

9

Features

• Central Office Quality

• No Front End Band Splitting Filters Required

• Single, Low Tolerance, 5V Supply

• Detects Either 12 or 16 Standard DTMF Digits

• Uses Inexpensive 3.579545MHz Crystal for Reference

• Excellent Speech Immunity

• Output in Either 4-Bit Hexadecimal Code or Binary

Coded 2-of-8

• Synchronous or Handshake Interface

• Three-State Outputs

• Excellent Latch-Up Immunity

Ordering Information

PART

NUMBER

TEMP.

PACKAGE

PKG. NO.

CD22202E

0 to 70

18 Ld PDIP

E18.3

CD22203E

0 to 70

18 Ld PDIP

E18.3

File Number

1695.3

DTMF Receivers/Generators

CD22202, CD22203

5V Low Power DTMF Receiver

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

http://www.intersil.com or 407-727-9207