DESCRIPTION
The LTC®4252 negative voltage Hot SwapTM controller allows a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions.

FEATURES
■ Allows Safe Board Insertion and Removal from a Live –48V Backplane
■ Floating Topology Permits Very High Voltage Operation
■ Programmable Analog Current Limit With Circuit Breaker Timer
■ Fast Response Time Limits Peak Fault Current
■ Programmable Soft-Start Current Limit
■ Programmable Timer with Drain Voltage Accelerated Response
■ ±1% Undervoltage/Overvoltage Threshold Accuracy (LTC4252A)
■ Adjustable Undervoltage/Overvoltage Protection
■ LTC4252-1/LTC4252A-1: Latch Off After Fault
■ LTC4252-2: Automatic Retry After Fault
■ Available in 8-Pin and 10-Pin MSOP Packages

APPLICATIONS
■ Hot Board Insertion
■ Electronic Circuit Breaker
■ –48V Distributed Power Systems
■ Negative Power Supply Control
■ Central Office Switching
■ High Availability Servers
■ ATCA