L7556

Data Sheet January 2000 L7556, L7557 Low-Power SLICs with Battery Switch Features s Auxiliary input for second battery, and internal switch to enable its use to save power s Low active power (typical 125 mW during on-hook transmission) s Supports meter pulse injection s Spare op amp for meter pulse filtering s –16 V to –60 V power supply operation s Distortion-free on-hook transmission s Convenient operating states: — Forward powerup — Disconnect (high impedance) — 2-wire wink (zero loop voltage) s Adjustable supervision functions: — Off-hook detector with longitudinal rejection — Ground key detector — Ring trip detector s Independent, adjustable, dc and ac parameters: — dc feed resistance — Loop current limit — Termination impedance s Thermal protection Description These electronic subscriber loop interface circuits (SLICs) are optimized for low power consumption while providing an extensive set of features. The SLICs include an auxiliary battery input and a b...