Demonstration circuit DC1555C is intended to demonstrate the performance of the LTC4365 and LTC4365-1 Undervoltage, Overvoltage and Reverse Supply Protection Controllers. The LTC4365/LTC4365-1 protect circuits from input voltages that may be too high, too low or negative. It operates by controlling the gates of two back-to-back connected MOSFETs to keep the output in a safe range. The OV and UV protection levels are adjusted by resistive dividers at the OV and UV pins. Asserting the SHDN pin disables the MOSFETs and places the controller in a low-current shutdown state. The FAULT pin is asserted when the Controller is in shutdown mode or when the input voltage is outside of the UV or OV level.