Milpitas, Calif. - Linear Technology Corp.'s LTC4214 hot-swap controller chip allows a board with a low-voltage negative supply to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast-feed forward path that limits peak current under worst-case catastrophic fault.
A slight overcurrent condition will trip the circuit breaker if it persists for an adjustable timer period. Larger overcurrent conditions will be controlled through active current limiting, maintaining a safe power level in the MOSFET.
Catastrophic overcurrent conditions that result from a short circuit will cause the circuit breaker to trip immediately, protecting the load and the MOSFET even more quickly than the active current limit loop. These features, and the separate soft-start sequence for in-rush current limiting, protect -5 volt, -12 V or ECL systems while taking up minimal board space.
The device's voltage monitor offers programmable undervoltage and overvoltage detectors that disconnect the load whenever the input supply exceeds the desired operating range. A powergood status output can enable the load or a power module at startup or disable it if the circuit breaker trips. The unit requires a supply of -6 V to -16 V to operate. It is best for -12-V systems or can be derived from the 3.3 V and the -5.2 V of a -5.2-V system.
The LTC4214 is housed in a 10-pin MSOP package. Pricing starts at $2.35 each for 1,000-piece quantities.
Call (408) 432-1900