Semiconductor

MSM7512B

4/12

PIN DESCRIPTION

Note :

I* : Internally pulled-up input pin.

11

—

+3 V to +5 V Power Supply

2

3

AI

I

Analog receive signal input.

3

5

AO

O

Analog transmit signal output.

4

6

EAI

I

External analog signal input.

The signal applied to this pin is transmitted from AO via transmit output

amplifier. When not using this pin, it should be left open.

5

7

GND

—

Ground, 0 V.

6

8

X1

I

3.579545 MHz crystal resonator should be connected to X1 and X2.

When applying external clock 3.579545 MHz to the device, it should be

applied to X2 (not X1) via an AC-coupling capacitor of 100 pF and X1

has to be opened.

710

X2

O

8

12

CLK

O

3.579545 MHz clock signal output.

913

RD

O

Modem receive serial data output.

Digital "1" and "0" correspond to "Mark" and "Space", respectively. When

CD (Carrier Detect) is off, RD is held at "Mark" state.

10

15

CD

O

FSK Receive signal and answer tone detect.

Digital "0" and "1" represent "Detect" and "Non-detect", respectively.

11

17

XD

I*

Modem transmit serial data input.

Digital "1" and "0" correspond to "Mark" and "Space", respectively.

12

18

RS

I*

FSK signal and answer tone transmit enable.

When digital "0" is applied to RS, transmitting becomes enable.

13

19

TEST

I*

Chip test input.

TEST should be open or digital "1".

14

20

MOD1

I*

Operation mode select.

Refer to Table 1.

15

22

MOD2

I*

16

24

AOG

I*

Analog transmit signal amplitude select.

Digital "1"

Æ –10 dBm Typ. at AO

Digital "0"

Æ –4 dBm Typ. at AO

Description

Name

I/O

RS GS-VK

No.