2

Rev. 7

July 1998

Data Sheet

AS2533...6

Pin Description

Pin #

Symbol

Function

23

M1

Microphone Inputs

24

M2

Differential inputs for the microphone (electret).

3RO

Receive Output

This is the output for driving a dynamic earpiece with an impedance of 140 to 300

Ω.

5A

GND

Analogue Ground

This is the analogue ground for the amplifiers.

28

RI

Receive Input

This is the input for the receive signal.

6

STB

Side Tone Balance Input

This is the input for side tone cancellation.

1LS

Line Current Sense Input

This is the input for sensing the line current.

27

LI

Line Input

This input is used for power extraction and line current sensing.

25

CS

Current Shunt Control Output

This N-channel open drain output controls the external high power shunt transistor for the

modulation of the line voltage and for shorting the line during make period of pulse dialling.

4V

DD

Positive Voltage Supply

This is the supply pin for the circuit.

26

V

SS

Negative Power Supply

8MO

Melody Output

PDM output of the melody generator for tone ringing. Hi-Z when not active.

21

FCI

Frequency Comparator Input

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

10

HS/DP

Hook Switch Input and Dial Pulse Output

This is an I/O that is pulled high by the hook switch when off-hook and an open drain pulls

it low during break periods of pulse dialling and flash.

11

OSC

Oscillator Input

Pin for ceramic resonator (3.58 MHz). Recommended: Murata CSA 3.58MG312AM.

9

LLC

Line Loss Compensation

Select pin for line loss compensation (see also figure 4 to 7).

LLC = A

LLC = V

LLC = V

22

LED

LED Output Driver

Output for driving an LED that will be flashing when in Programme/Mute state.

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