Compact Dual Low Voltage Hot Swap Controller

The LTC4224 Dual Low Voltage Hot Swap™ controller allows a board to be safely inserted and removed from a live backplane. It controls two supplies with external N-channel MOSFETs and operates with one supply as low as 1V provided the other supply is 2.7V or greater. The LTC4224 can ramp up the supplies in any order and at adjustable ramp rates. To minimize the number of external components and PCB area, the gate capacitor is optional, all timing delays are generated internally, and the ON pins have integrated pull-up currents.

Protection against overcurrent faults is provided by a fast-acting current limit and timed circuit breakers. A FAULT pin signals overcurrent faults. The LTC4224-1 remains off after a fault, while the LTC4224-2 automatically tries to apply power again after a four second cool-down period.

Applications

* Optical Networking

* Low Voltage Hot Swap

* Electronic Circuit Breakers

* Allows Safe Board Insertion and Removal from a Live Backplane

* Controls Load Voltages from 1V to 6V

* No Gate Components Required

* Adjustable Current Limit with Circuit Breaker

* Limits Peak Fault Current in ≤1μs

* No External Timing Capacitor Required

* Adjustable Supply Voltage Power-Up Rate

* Gate Drive for External N-channel MOSFET

* LTC4224-1: Latchoff After Fault

* LTC4224-2: Automatic Retry After Fault

* 10-Lead MSOP and 3mm × 2mm DFN Packages