MC145442

•MC145443

MOTOROLA

10

20

6

9

19

10

1

17

15

16

DTMF

INPUT

20 k

Ω

RTx

600

Ω

+

10

Ω

TIP

RING

*

0.1

µF

4

19

10

18

CDT

VAG

FB

Exl

RxA1

TxA

RxA2

DSI

TLA

VDD

MC145442/3

GND

CDA

MODE

LB

SQT

RxD

TxD

CD

Xin

Xout

8

7

12

3.58

MHz

11

15

13

8

2

3

7

6

8

7

9

2

4

+ 5 V

Rx3

Rx2

Tx1

Rx1

Tx2

GND

STBY

TxEN

DI1

DI2

DO1

VCC

MC145407

EIA–232–D

DB–25

CONNECTOR

0.1

µF

VDD

10

µF

0.1

µF

0.1

µF

CCDT

0.1

µF

CFB

RDSI

CDSI

RTLA

CCDA

0.1

µF

10 k

Ω

VDD

VSS

10 k

Ω

10 k

Ω

0.1

µF

0.1

µF

20

C1+

C1–

18

C1+

C1–

1

3

0.1

µF

17

MMBZ15VDLT1 X 3

* Line Protection Circuit

Figure 7. Typical MC145442/MC145443 Applications Circuit