Datasheet AS2525

Revision 2.1

Page 3 of 27

Pin #

Symbol

Type

Description

19

RECI

AI

Analogue input for the handsfree receive path. Should be connected to RO via a coupling

capacitor.

20

RECV

AI

Analogue input for receive voice switching path.

21

RO

AO

Output for driving a dynamic earpiece with an impedance from 150

22

Supply

Positive Power Supply.

23

Supply

Special ground for the internal amplifiers.

24

CBN

AI

Analogue input pin for connecting a capacitor for background noise monitoring.

25

CM

DO

This is an output for controlling the external switching converter. During ringing it converts

the ring signal into a 4V supply voltage.

26

Supply

Loudspeaker Power Supply

High power supply for the output driver stage.

27

28

LO1

LO2

AO

Output pins for a 32

29

Supply

Power supply pin for LO1-LO2 output amplifier.

30

DM/HM

DI

Digital input for choosing between LD and MF dialing or choosing handset and headset

mode. See “Table 3: Parameter settings” for further details. This pin is scanned after manual

off-hook only.

31

FCI

DI

This is a Schmitt-trigger input for ring frequency discrimination. Disabled during off-hook.

32

LED

DO

Digital output for connecting 2 mA LED to indicate handsfree mode.

33

OSC

Input for ceramic resonator 3.58 MHz.

34

35

36

R1

R2

R3

DI/O

Keyboard

(see Figure 1: Keyboard Layout).

37

38

39

40

C1

C2

C3

C4

DI/O

Keyboard

(see Figure 1: Keyboard Layout).

41

CLK

DO

Clock output for 3-wire bus.

If signal is not activated, a pull down resistor (100 k

42

DI

DI

Data input of 3-wire bus.

If signal is not activated, a pull down resistor (100 k