Data Sheet AS2540

Revision 3.1

Page 2 of 18

Pin Description

Pin #

Symbol

Function

15

RFD

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

7LS

Input for sensing the line current

5LI

Input used for power extraction and line current sensing

6RI

Input for ac-separated receive signal

2STB

Input for side tone cancellation network

3CS

N-channel open drain output to control the external high power shunt transistor for synthesising ac- and

dc- impedance, modulation of line voltage and shorting the line during make periods of pulse dialling

8CI

Input pin for the capacitor to program a complex impedance

16

DPn

Open drain output pulls low during break periods of pulse dialling and flash

17

EHS

Schmitt Trigger Input to detect an electronic off-hook.

18

MHS

Schmitt Trigger Input to detect a manual off-hook.

19

MODE

-4/-6dBm

—> DLS open

-6/-8dBm

—> DLS-r1

-8/-10dBm

—> DLS-r2

45mA-75mA

—> LLC open

20mA-50mA

—> LLC-r3

None

—> LLC-r4

28

MO

Ring

PDM output of the ring melody generator.

11

VDD

Positive Power Supply

4

VSS

Negative Power Supply