The LTC4242 Hot Swap™controller allows safe board insertion and removal for two independent slots on a PCI Express backplane. External N-channel transistors control the 12V and 3.3V supplies while integrated switches control the 3.3V auxiliary supplies. Both 12V and 3.3V supplies can be ramped up at an adjustable rate. Dual level circuit breakers and fast active current limiting protect all supplies against overcurrent faults.A supply filter at the VCCpin allows the LTC4242 to endure supply transients. TheENinput detects the presence of a card in the PCI Express slot. TheFAULTandAUXFAULToutputs alert the system of overcurrent conditions on the main and auxiliary supplies, respectively.PGOODandAUXPGOODoutputs indicate proper main and auxiliary supply outputs.ApplicationsPCI Express-Based PC and ServersHot Swap Application for Triple Supply Systems