LT4363 Surge Arrester protects loads from high voltage transients. It regulates the output during an overvoltage event, such as a load dump in a vehicle, by controlling the gate of an external n-channel MOSFET. The output is limited to a safe value, allowing the load to continue working.
Typical Application
The LT4363 also monitors the voltage drop between the SNS and the OUT pins to prevent overcurrent failures. An internal amplifier limits the voltage across the current-sensing resistor to 50mV. Under any fault condition, timer startup is inversely proportional to MOSFET stress. Before the timer expires, FLT pin pulls down warning of impending power outage. If this persists, the MOSFETs are turned off. The LT4363-1 remains off until reset, while the LT4363-2 restarts after the cooling off period. Two precision comparators can monitor the overvoltage (OV) and undervoltage (UV) conditions of the input power supply.
When the potential is below the UV threshold, the external mosFETs remain off. The MOSFET cannot be turned on if the input voltage is higher than the OV threshold. Back-to-back MosFeTs can be used for reverse input protection of Schottky diodes, reducing voltage drop and power loss. During shutdown, a shutdown pin reduces the static current to less than 7µA.
Block Diagram
