LTC1643 Datasheet

• Allows Safe Board Insertion and Removal from aLive PCI Slot
• Works on either a Motherboard (LTC1643H) orCompactPCITM Card (LTC1643L/LTC1643L-1)
• Controls –12V, 3.3V, 5V, 12V Supplies
• Programmable Foldback Current Limit withCircuit Breaker
• User-Programmable Supply Voltage Power-Up Rate
• High Side Drive for External N-Channel MOSFETs
• –12V and 12V On-Chip Switches
• Fault and Power-Good Outputs

• PCI-Based Servers
• CompactPCICompliant Boards

The LTC®1643 is aHot SwapTM controllerthat allows a boardto be safely inserted and removed from a live PCI-Bus slot.Two external N-channel transistors control the 3.3V and 5Vsupplies while on-chip switches control the –12V and 12Vsupplies.All supply voltages can be ramped up at aprogrammable rate. An electronic circuit breaker protects all foursuppliesagainstovercurrentfaults.Thefoldbackcurrentlimitfeature limits current spikes and power dissipation whenshorts occur and allows boardswith large capacitances to bepowered upwithouttripping the circuit breaker. ThePWRGDoutput indicates when all of the supply voltages are withintolerance and the FAULT output indicates an overcurrentcondition.TheON(LTC1643H)/ON(LTC1643L/LTC1643L-1)pin is used to cycle the board power or reset the circuitbreaker. The LTC1643L-1 has the ±12V power good comparators disabled.

The LTC1643 is available in a 16-pin narrow SSOP package.