LTC4253A-ADJ

Obsolete

-48V Hot Swap Controller with Sequencer

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Overview

Obsolete - Contact Analog Devices for Potential Replacement
Allows Safe Board Insertion and Removal from a Live – 48V Backplane
Floating Topology Permits Very High Voltage Operation
Adjustable Analog Current Limit with Breaker Timer
Fast Response Time Limits Peak Fault Current
Adjustable Undervoltage/Overvoltage Protection with ±1% Threshold Accuracy

Three Sequenced Power Good Outputs
Adjustable Soft-Start Current Limit
Adjustable Timer with Drain Voltage Accelerated Response
Latchoff After Fault
Available in 20-Pin SSOP and 20-Pin (4mm × 4mm) QFN Packages

The LTC4253A-ADJ negative voltage Hot Swap^™ 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. The LTC4253A-ADJ latches off after a circuit fault.

Undervoltage and overvoltage detectors with adjustable thresholds and hystereses disconnect the load whenever the input supply exceeds the desired operating range. The LTC4253A-ADJ's supply input is shunt-regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial start-up and controls the circuit breaker's response time. The circuit breaker's response time can be accelerated by sensing excessive MOSFET drain voltage. An adjustable soft-start circuit controls MOSFET inrush current at start-up.

Three power good outputs can be sequenced to enable external power modules at start-up or disable them if the circuit breaker trips. The LTC4253A-ADJ is available in 20-pin SSOP and 20-pin (4mm × 4mm) QFN packages.