The LTC4214 is a negative Hot Swap controller in a MSOP package. The device allows a board with a low voltage negative supply to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting, and a fast feed forward path that limits peak current under worst-case catastrophic fault. A slight over-current condition will trip the circuit breaker if it persists for an adjustable timer period. Larger over-current conditions will be controlled through active current limiting, maintaining a safe power level in the MOSFET.