PIN DESCRIPTION

Pin

Number

Name

Type

Description

1

Rx/Tx

Digital

Rx or Tx mode selection input

2

RESET

Digital

Logic reset and power-down mode input. Active when low.

3

TEST4

Digital

Test input which selects the Tx band-pass filter input (TxFI) when high.

4

TEST3

Digital

Test input which gives an access to the clock recovery input stage. This input is selected

when TEST1 is high.

5

RxD

Digital

Synchronous receive data output

6

CLR/T

Digital

Rx or Tx clock according to the functional mode

7

RxDEM

Digital

Demodulated data output

8

DGND

Supply

Digital ground

Supply

Digital positive supply voltage : 5V

± 5%

10

TEST1

Digital

Test input which cancels the Tx to Rx mode automatic switching and validates TEST3

input. Active when high.

11

TEST2

Digital

Test input which reduces the Tx to Rx mode automatic switching time. Active when high.

12

TxD

Digital

Transmit data input

13

XTAL2

Digital

Crystal oscillator output

14

XTAL1

Digital

Crystal oscillator input

15

CHS

Digital

Channel selection input

16

BRS

Digital

Baud rate selection input

17

AFCF

Analog

Automatic frequency control output for connecting compensation network.

18

Supply

Digital negative supply voltage : -5V

± 5%

19

IFO

Analog

Intermediate frequency filter output

20

DEMI

Analog

FSK demodulator input

21

Supply

Analog negative supply voltage : -5V

± 5%

22

AGND

Supply

Analog ground : 0V

23

Supply

Analog positive supply voltage : 5V

± 5%

24

RAI

Analog

Receive analog input

25

RxFO

Analog

Receive filter output

26

TxFI

Analog

Transmit filter input (selected when TEST4 is high)

27

ALCI

Analog

Automatic level control input

28

ATO

Analog

Analog transmit output

ST7536

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