The HC5549 Subscriber line

interface circuit is a 100V

diellectrically isolated bipolar

integrated circuit for use in

short loop ISDN, PABX and

Pairgain applications. The HC5549 has been optimized for low

power as required for battery backed remote terminals or for

applications requiring emergency powering from the line such

as European ISDN NT1+ designs.

A high and low voltage battery supply may be connected to

the HC5549 so that power dissipation can be lowered in the

off hook condition in these short loop applications. The high

battery supply can be used in the on-hook condition to allow

interfacing to fax and answering machines that require 48V

to detect end of call status. The HC5549 also has a low

power standby state with very low power consumption

(35mW) resulting in exceptionally low battery drain while

providing continued loop supervision.

The HC5549 provides loop current, ground key and ring trip

detect functions as well as an alarm output to indicate

thermal overload.

2-wire to 4-wire and 4-wire to 2-wire conversion is provided

and impedance matching is achieved using a single external

network. The HC5549 is compatible with dual and single

supply switched capacitor or DSP codec/filters

Features

? Dual Battery Operation

? Single Additional +5V Supply

? Low Standby Power Consumption (48V, 35mW)

? On Hook Transmission

? Tip and Ring Disconnect

? Soft or Hard Polarity Reversal

? Supports 12kHz or 16kHz Pulse Metering

? Ring Relay Driver

? On Chip 2-wire AC/DC Loopback

? 0°C to 70°C or -40°C to 85°C Ambient Temp Range

? Low External Component Count

? Pb-Free Available (RoHS Compliant)

Applications

? ISDN NT1+ Terminals

? Pairgain Remote Termination

? PABX and Key Systems