I like to use OmniFETs for MOSFETs because they have internal protection against ESD so I am unlikely to damage them while handling and then when they don't work I don't have to wonder if it was damaged or I have a circuit mistake. These are n-channel FETs, but now I need a p-channel FET. I tried to find one Mouser and Digikey, but was unsuccessful. Is there such a thing?
It would basically be a MOSFET and a diode in one package. Other things like over-current and over-temperature protection would also be nice, but are less important.
Best Answer
The overvoltage clamp is not an ESD protection, it is a protection against an overly high input voltage during use, preventing the transistor from being turned on if too high a voltage is being applied.
The clamp will change the transistor from being switched on to being switched off electronically in case it detects overvoltage. It does not remove the voltage, only prevent a current from flowing. Sufficient ESD will still destroy the transistor.
The whole protection part can only be constructed for n-channel FETs, and not for p-channel FETs for technical reasons:
The protection circuits have to be powered. We need protection only when conductive, because that is when heat is created inside the transistor. When conductive, the source-drain voltage probably is quite low. So the only way to draw power is from gate.
Now a pfet has no voltage on gate when conductive, meaning an active protection cannot be powered.
Also, in amplifiers, where pfets are often used, it is a bad idea to use individually protected transistors. The protection circuits are not very precise, meaning the individual transistors will not turn off at the same time. Turning off only one transistor of a symmetric setup can lead to very bad results.