New Industry Products

Linear’s Hot Swap Controller Provides Digital Monitoring

March 26, 2006 by Jeff Shepard

A new four-supply Hot Swap™ controller from Linear Technology features an onboard 8-bit ADC and I2C compatible interface. The LTC4245 has the flexibility to support 3.3V, 5V and ±12V for CompactPCI or 12V, 3.3V and auxiliary 3.3V for PCI Express and provides integrated digital power monitoring by measuring card voltages, currents and recording fault conditions.

The LTC4245 turns the board supply voltage on and off in a controlled manner. It offers programmable dI/dt softstart and active current limiting for a controlled supply ramp. A two-level filtered circuit breaker and fast current limit protects the card from over current faults while allowing operation through brief load current surges.

The controller disconnects the load if it remains in current limit beyond the time-out delay and can be configured to latch off or auto-retry following the event. All supplies utilize external N-channel MOSFETs for minimum on-resistance and optimal load current capability. The input pins for the ±12V supplies withstand transients up ±20V, respectively, as necessary for card resident applications such as CompactPCI.

The LTC4245 has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a board, and turn off the pass transistors if an external supply monitor fails to indicate power good within a timeout period.

Specified over the commercial and industrial temperature ranges, the LTC4245 is available from stock in 36-lead SSOP and 38-lead 5mm x 7mm QFN packages. Pricing begins at $5.95 each in 1,000-piece quantities.