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High Voltage limiting for LTC4380

Category: Hardware
Product Number: LTC4380


I have a application where i want to limit the voltage transients and current in a 140VDC circuit. I am looking at the datasheet of the LTC4380 and the application circuit in figure 11 shows how to accomplish this with a 70VDC limit. If i want to use the 4380 in my application, i am thinking that i will need to change the application circuit in figure 11 with the following:

- Tie SEL to VCC so that my clamping voltage is at 50V

- Replace the 43V zener diode connected to the GND with two 47V zeners in series

By doing this, will my voltage clamp be set at 47V+47V+45V = 139V?

Also will i need to increase the 33V zener that is connected to VCC to a higher voltage level?