Floating "surge stopper" IC clamps 500V and more, allows cool-down period

Milpitas, Calif.—Transients and surges are an unpleasant, unavoidable, and even hazardous concern in industrial, auto, and avionic applications, due to motors, coupled overvoltages, supply failures or misconnections, and other real-world impositions. So, what to do? You can use a combination of inductors, capacitors, fuses, and transient voltage suppressors to clamp the situation.

As an alternative, you can use an IC such as the LTC4366 from Linear Technology Corp. This floating surge stopper operates from 9V to 500V and higher, employing an adjustable topology to allow for high-voltage operation which is independent of the voltage rating of the IC itself—the maximum operating voltage is set by the breakdown rating of the associated resistors and MOSFETs. It uses two internal shunt regulators which work in conjunction with external voltage-dropping resistors to generate the IC's supply rails.

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In operation, the LTC4366 reacts to input-supply overvoltage by switching the gate of the external N-channel MOSFET, and regulates the output to a user-defined level during the transient. The load remains operational and powered while the overvoltage is dropped across the MOSFET.

Two options of the surge stopper IC are available: The -1 version latches and stays latched after a fault, while the -2 version will automatically retry after a "cool-down" period of nine seconds. In shutdown mode, the LTC4366 supply current drops below 20 μA.

Packaging, pricing, and availability: The LTC4366 is available in an 8-lead TSOT and 3 × 2 mm DFN packages. Temperature options are commercial (0⁰C to 70⁰C), industrial (-40⁰C to 85⁰C), and automotive (-65⁰C to 150⁰C). Prices begin at $2.66 (1000 pieces); production quantities are available now.

For more information: go to http://www.linear.com/LTC4366.