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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 sub
L7556 Datasheet
