Description
This general-purpose electronic subscriber loop interface circuit (SLIC) is optimized for low cost, while still providing a satisfactory set of features.
The L9218 is pin-for-pin compatible with the Agere L9219 and L9217 SLICs.
The L9218 requires a 5 V power supply and single battery to operate. This is a forward battery only device. Additionally, a low-power scan mode, wherein all circuitry except the off-hook supervision is shut down to conserve power, is available.

Features
■ Basic forward battery only SLIC functionality at a low cost
■ Pin compatible with Agere Systems Inc. L9219 and L9217 SLIC
■ Low active power (typical 138 mW during on-hook transmission)
■ Low-power scan mode for low-power, on-hook power dissipation (59 mW typical)
■ Minimal external components
■ Distortion-free, on-hook transmission
■ Convenient operating states:
    — Forward battery low current limit
    — Forward battery high current limit
    — Low-power scan
    — Disconnect (high impedance)
■ Adjustable supervision functions:
    — Off-hook detector with hysteresis
    — Ring trip detector
■ Logic controlled high and low current limit
■ Two gain options to optimize the codec interface
■ Thermal protection with thermal shutdown indication