The LT1641 is an 8-pin Hot Swap controller that allows a board to be safely inserted and removed from a live backplane. Using an external N-channel pass transistor, the board supply voltage can be ramped up at a programmable rate. A high side switch driver controls an N-channel gate for supply voltages ranging from 9V to 80V. The chip features a programmable analog foldback current limit circuit. If the chip remains in current limit for more than a programmable time, the N-channel pass transistor turns off and is optionally set to automatically restart after a time-out delay. The PWRGD output indicates when the output voltage, sensed by the FB pin, is within tolerance. The ON pin provides programmable undervoltage lockout. The LT1641-1/LT1641-2 are recommended for new designs. The LT1641 is available in the 8-lead SO package.
