Features

• Controls –12V, 3.3V, 5V and 12V Supplies
• ±14.4V Absolute Maximum Rating for 12V_IN and –12V_IN Input Pins
• Insensitive to Supply Voltage Transients
• Adjustable Foldback Current Limit with Circuit Breaker
• LOCAL_PCI_RST# Logic On-Chip
• PRECHARGE Output Biases I/O Pins During Card Insertion and Extraction
• LTC4244-1 Designed for Applications without –12V
• Available in 20-Lead Narrow SSOP Package

Typical Application

Description

The LTC®4244/LTC4244-1 are Hot Swap™ controllers that allow a board to be safely inserted into and removed from a CompactPCI™ bus slot. External N-channel transistors control the 5V and 3.3V supplies while on-chip switches control the ±12V supplies. The 3.3V and 5V supplies can be ramped up at an adjustable rate. Electronic circuit breakers protect all four supplies against overcurrent faults. After the power-up cycle is complete, the TIMER pin capacitor serves as auxiliary V_CC allowing the LTC4244/ LTC4244-1 to function without interruption in the presence of voltage spikes on the 12VIN supply. The PWRGD output indicates when all four supplies are within tolerance. The OFF/ON pin is used to cycle 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 combined on-chip with HEALTHY# in order to generate LOCAL_PCI_RST#.