mosfets have capacitance on the gate. this means you can't drive them directly using cmos gates or you'll cook the outputs.
in this example I've got a 2SK3262 N MOSFET being driven by a logic gate. the ammeter shows the current required to charge the gate to 5V is 23mA; well above the rated source current for the gate output. the faster the rise time of the signal, the more current gets sourced.
fixes for this:
- use a longer rise and fall time (which reduces switching frequency as well).
- use a gate drive transistor pair.
- use TTL instead of cmos
