L7557 Datasheet | Lucent Technologies

Features s Auxiliary input for second battery, and internal switch to enable its use to save power s Low active power (typical 125 m W 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...