1

TM

FN1696.5

CD22204

5V Low Power Subscriber DTMF Receiver

The CD22204 complete dual tone multiple frequency (DTMF)

receiver detects 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 reference) and a bias

resistor. Extremely high system density is possible through

the use of the Alternate Time Base (ATB) output of a crystal

connected CD22204 receiver to drive the time bases of up to

10 additional receivers. This is a monolithic integrated circuit

fabricated with low power, complementary symmetry CMOS

processing. It only requires a single power supply.

The CD22204 employs state-of-the-art ‘‘switched-capacitor’’

filter technology, resulting in approximately 40 poles of filtering

and digital circuitry on the same CMOS chip. The analog input

is preprocessed by 60Hz reject and bandsplitting filters and

then zero-cross detected to provide AGC. Eight bandpass

filters detect the individual tones. Digital processing is used to

measure the tone and pause durations and provides the

correctly coded and timed digital outputs. The outputs

interface directly to standard CMOS circuitry and are three-

state enabled to facilitate bus oriented architectures.

Functional Diagram

Features

• No Front End Band Splitting Filters Required

• Single Low Tolerance 5V Supply

• Three-State Outputs for Microprocessor Based

Systems

• Detects all 16 Standard DTMF Digits

• Uses Inexpensive 3.579545MHz Crystal

• Excellent Speech Immunity

• Output in 4-Bit Hexadecimal Code

• Excellent Latch-Up Immunity

Pinouts

CD22204 (PDIP)

TOP VIEW

Part Number Information

PART

NUMBER

TEMP.

PACKAGE

PKG. NO.

CD22204E

0 to 70

14 Ld PDIP

E14.3

HIGH B/P

FILTERS

LOW B/P

FILTERS

VOLTAGE

REG./REF.

CHIP

CLOCKS

ATB

XEN

11

6

10

9

48

5

12

2

1

14

13

3

DV

D1

D4

D8

EN

XIN

XOUT

D2

ANALOG IN

7

NC

NOTE: Pin numbers are for PDIP.

D2

D1

EN

NC

XEN

ANALOG

D4

D8

DV

ATB

XIN

XOUT

1

2

3

4

5

6

7

14

13

12

11

10

9

8

IN

Data Sheet

November 2002

OBSO

LETE

PROD

UCT

NO RE

COMM

ENDE

D REP

LACE

MENT

conta

ct our

Techn

ical Su

pport

Cente

r at

1-888-

INTER

SIL or

www.i

ntersi

l.com/

tsc

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

1-888-INTERSIL or 321-724-7143

Copyright © Intersil Americas Inc. 2002. All Rights Reserved

All other trademarks mentioned are the property of their respective owners.