Features

• Allows Safe Board Insertion and Removal from a Live, CompactPCI™ Bus
• Controls 3.3V and/or 5V Supplies
• Programmable Foldback Current Limit During Power-Up
• Dual Level Circuit Breakers Protect Supplies from Overcurrent and Short-Circuit Faults
• Local_PCI_RST# Logic On-Chip
• PRECHARGE Output Biases I/O Pins During Card Insertion and Extraction
• User Programmable Supply Voltage Power-Up Rate
• 15V High Side Drive for External N-Channels
• PWRGD, RESETOUT and FAULT Outputs

Typical Application

Description

The LTC1646 is a hot swap controller that allows a board to be safely inserted and removed from a live CompactPCI bus slot. Two external N-Channel transistors control the 3.3V and 5V supplies. The supplies can be ramped-up in current limit or at a programmable rate. Electronic circuit breakers protect both supplies against overcurrent fault conditions. The PWRGD output indicates when all of the supply voltages are within tolerance. The OFF/ON pin is used to cycle the board power or reset the circuit breaker. The PRECHARGE output can be used to bias the bus I/O pins during card insertion and extraction. PCI_RST# is logically combined on-chip with HEALTHY# in order to generate LOCAL_PCI_RST# which can be used to reset the CPCI card logic if either of the supply voltages is not within tolerance.

The LTC1646 is available in the 16-pin narrow SSOP package.