Description
The L8574 is a resistive subscriber line interface circuit (SLIC) that is optimized for long loop applications, such as Bellcore TR-NWT-000057 requirements for digital loop carrier (DLC) applications. It interfaces the low-voltage circuits on an analog line card to the Tip/Ring subscriber loop. The L8574 does not supply dc current to the subscriber loop; external resistors are used for this purpose.

Features
■ Low-power scan mode for low on-hook power dissipation (55 mW max)
■ Low active power dissipation; talk or on-hook transmission (240 mW max)
■ Distortion-free on-hook transmission
■ Eight operating states via latched paralleled data inputs with channel select feature
■ Precision fixed 28 mA current limiter
■ Integrated protection
■ No external protection device required
■ Integrated ringing access relay
■ Ring trip detector
■ Loop closure detector with hysteresis
■ Relay driver
■ Battery noise cancellation
■ Thermal protection
■ 44-pin, surface-mount, plastic package (PLCC)