PCI-Bus with 3.3V Auxiliary Hot Swap Controller

The LTC4241 is a Hot Swap controller that allows a board to be safely inserted and removed from a live PCI-bus slot. It has a primary controller that controls the four PCI supplies and an independent auxiliary controller to control the 3.3V auxiliary supply. External N-channel transistors are used to control the 3.3V, 5V and 3.3V auxiliary supplies while on-chip switches control the –12V and 12V supplies. The 3.3V, 5V and 3.3V auxiliary supplies can be ramped up at an adjustable rate. Electronic circuit breakers protect all five supplies against overcurrent faults. The foldback current limit feature reduces current spikes and power dissipation when shorts occur. The PWRGD output of the primary controller indicates when all four PCI supplies are within tolerance. The FAULT output indicates an overcurrent condition for any of the five supplies.

The LTC4241 is available in the 20-pin narrow SSOP package.

Applications

* PCI-Based Servers

* Computer Systems

* Allows Safe Board Insertion and Removal from a Live PCI Slot * Controls 3.3V, 5V, –12V, 12V and 3.3V Auxiliary Supplies * Independent 3.3V Auxiliary Supply Hot Swap™ Controller * Adjustable Foldback Current Limit with Circuit Breaker * Adjustable Supply Voltage Power-Up Rate * High Side Drive for External N-Channel FETs * –12V and 12V On-Chip Switches * Fault and Power Good Outputs