LT4256-2 Datasheet

• 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
• Programmable Supply Voltage Power-Up Rate
• Undervoltage Protection
• Automatic Retry (LT4256-2)
• Available in an 8-Pin SO Package

• 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

The 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 LT4256-2 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 PWRGD output indicates when the output voltage rises above a programmed level. An external resistor string from V_CC provides programmable undervoltage protection.

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

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