DESCRIPTION
The LT®1641-1/LT1641-2 are 8-pin Hot SwapTM control lers that allow 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 chips feature a programmable analog foldback current limit circuit. If the chips remain in current limit for more than a programmable time, the N-channel pass transistor is either latched off (LT1641-1) or is set to automatically restart after a time-out delay (LT1641-2). 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 available in the 8-lead SO package.

FEATURES
■ Allows Safe Board Insertion and Removal from a Live Backplane
■ Controls Supply Voltage from 9V to 80V
■ Programmable Analog Foldback Current Limiting
■ High Side Drive for an External N-Channel
■ Latched Operation Mode (LT1641-1)
■ Automatic Retry (LT1641-2)
■ User Programmable Supply Voltage Power-Up Rate
■ Undervoltage Lockout
■ Overvoltage Protection
■ Both are available in 8-Lead SO Package

APPLICATIONS
■ Hot Board Insertion
■ Electronic Circuit Breaker
■ Industrial High Side Switch/Circuit Breaker
■ 24V/48V Industrial/Alarm Systems