The LT4250L/LT4250H are 8-pin, negative 48V Hot Swap™ controllers that allow a board to be safely inserted and removed from a live backplane. Inrush current is limited to a programmable value by controlling the gate voltage of an external N-channel pass transistor. The pass transistor is turned off if the input voltage is less than the programmable undervoltage threshold or greater than the overvoltage threshold. A programmable current limit protects the system against shorts. After a 500μs timeout the current limit activates the electronic circuit breaker. The PWRGD (LT4250L) or PWRGD (LT4250H) signal can be used to directly enable a power module. The LT4250L is designed for modules with a low enable input and the LT4250H for modules with a high enable input.
The LT4250L/LT4250H are available in 8-pin PDIP and SO packages
Feature
- Allows Safe Board Insertion and Removal from a Live –48V Backplane
- Circuit Breaker Immunity to Voltage Steps and Current Spikes
- Programmable Inrush and Short-Circuit Current Limits
- Pin Compatible with LT1640L/LT1640H
- Operates from –18V to –80V
- Programmable Overvoltage Protection
- Programmable Undervoltage Lockout
- Power Good Control Output
- Bell-Core Compatible ON/OFF Threshold
Applications
- Central Office Switching
- –48V Distributed Power Systems
- Negative Power Supply Control
(Picture: Pinout)
