Positive High Voltage Hot Swap Controllers

The LT4256-1/LT4256-2 are high voltage Hot Swap™ controllers that allow a board to be safely inserted and removed from a live backplane. An internal driver drives an external N-channel MOSFET switch to control supply voltages ranging from 10.8V to 80V.

The LT4256-1/LT4256-2 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 and the PWRGD output asserts low. The LT4256-2 automatically restarts after a time-out delay. The LT4256-1 latches off until the UV pin is cycled low.

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

The LT4256 can be used as an upgrade to LT1641 designs.

The LT4256-1 and LT4256-2 are available in an 8-pin SO package that is pin compatible with the LT1641.

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

* Overcurrent Fault Detection

* Drives an External N-Channel MOSFET