What are possible failure sources for a schottky diode? Overheating, overvoltage, overcurrent (leading to overheating) anything else?
I am currently measuring our new prototype device. It works fine, does not draw more current than expected and stays relatively cool (hottest point on the PCB is 50°C at the buck converter.)
In front of the buck I have a schottky diode for reverse voltage protection:
I left the device running for some minutes, current draw on the 3V3 rail was below 500mA, 24V current must have been below 100mA. Then I saw a small lightning, like ESD, and the device stopped working (no current draw). On closer investigation I found a small hole in the middle of the schottky diode package, and the diode was open circuit.
I would rule out ESD, as the device was lying on the desktop and nothing touched it. The device was powered by a lab power supply. Any ideas why the component failed?