LT4356-1

Overvoltage Protection Regulator and Inrush Limiter

The LT4356-1 surge stopper protects loads from high voltage transients. It regulates the output during an overvoltage event, such as a load dump in automobiles. This is done by controlling the gate of an external N-Channel MOSFET. The output is limited to a safe value thereby allowing the loads to continue functioning. The LT4356-1 also monitors the voltage drop between the VCC and SNS pins to protect against overcurrent faults. An internal amplifier limits the current sense voltage to 50mV. In either fault condition, a timer is started inversely proportional to MOSFET stress. If the timer expires, the FLT pin pulls low to warn of an impending power down. If the condition persists, the MOSFET is turned off.

The spare amplifier may be used as a voltage detection comparator or as a linear regulator controller driving an external PNP pass transistor.

Back-to-back FETs can be used in lieu of a Schottky diode for reverse input protection, reducing voltage drop and power loss. A shutdown pin reduces the quiescent current to less than 5µA during shutdown.