Positive High Voltage Hot Swap Controller with Open-Circuit Detect

The LT4256-3 is a high voltage Hot Swap™ controller that allows a board to be safely inserted and removed from a live backplane. An internal driver controls the high side N-channel MOSFET gate for supply voltages ranging from 10.8V to 80V. The part features an open-circuit detect (OPEN) output that indicates abnormally low load current conditions.

The LT4256-3 also features an adjustable analog foldback current limit. If the supply remains in current limit for more than a programmable time, the N-channel MOSFET shuts off, the PWRGD output asserts low and the LT4256-3 either automatically restarts after a time-out delay or latches off until the UV pin is cycled low (depending on the status of the RETRY pin).

The PWRGD output indicates when the output voltage rises above a programmed level. An external resistor string from VCC provides programmable undervoltage and overvoltage protection.

The LT4256-3 is available in a 16-lead SSOP package.

Retry / Latch Off

Features

Package

LT4256-1

Latch Off

UV

SO-8

LT4256-2

Retry

UV

SO-8

LT4256-3

Latch Off or Retry

UV/OV, Open Circuit Detect

SSOP-16

Applications

* Hot Board Insertion

* Electronic Circuit Breaker/Power Bussing

* Industrial High Side Switch/Circuit Breaker

* 24V/48V Industrial/Alarm Systems

* Ideally Suited for 12V, 24V and 48V Distributed Power Systems

* 48V Telecom Systems

* Allows Safe Board Insertion and Removal from a Live Backplane

* Controls Supply Voltage from 10.8V to 80V

* Foldback Current Limiting

* Open Circuit and Overcurrent Fault Detect

* Drives an External N-Channel MOSFET