Description

The L7585G Full-Feature, Low-Power Subscriber Loop Interface Circuit (SLIC) and Switch integrates the battery feed, test access relay, and ringing relay that are necessary to interface a codec to the tip and ring of a subscriber loop into one low-power, low-cost package. It is built using a 90 V complementary bipolar (CBIC) process and a 320 V Bipolar-CMOSDMOS (BCDMOS) process. The device is available in a 44-pin MQFP package.

The device can be connected directly to the Agere Systems Inc. T8531/T8536 16-Channel Programmable Codec Chip Set without the need for any ac interface components.

Features

■ Low active power

■ Quiet tip/ring polarity reversal

■ Distortion-free on-hook transmission

■ 35 V to 60 V power supply operation

■ 14 operating states:

— Forward battery active

— Reverse battery active

— Ground start (3)

— Forward battery ring open

— Reverse battery ring open

— Reverse battery tip open

— High impedance

— Ringing (2)

— Low current (2)

— Disconnect

■ Self-test in all operating states

■ Independent, adjustable ac and dc parameters:

— Switchhook detector threshold

— Loop current limit

— dc feed resistance

— Termination impedance

■ Integrated ringing access relay

■ Integrated test-in relay

■ Integrated relay driver

■ Integrated ring trip detector

■ Thermal protection

■ 44-pin, metric quad flat package (MQFP)