I want to protect the input of my 5V micro-controller from two types of disasters, I am detecting a low on the input (0V):
The input is from a switch. When the switch is on it provides a ground.
Over-voltage protection on the input (the input can range between 5V to 24V DC). Hence the over-voltage protection must be clamped to 24V DC MAX.
The minimum voltage must be greater than -0.3V. The device states that the input voltage must not be less than -0.3V. The device is not a common device, hence part numbers or datasheets are not available. I just have the specs for the device
Hence I have the below schematic.
D1 is a Zener diode that a Zener voltage of 5.1V and D2 is a Schottky diode with a forward voltage drop of 0.2V, which means any negative voltage is clipped at -0.2V.
I have not specced any components because there is no stock currently for the diodes
I want to know which placement of components is better, placement 1 or placement 2?