Oznog
Active Member
Stupid PIC MOSFET driver...
I finally found why this thing goes nuts. Even though I'm just driving a gate, no load on the FET, the pin and rail were seeing spikes to 6.5v or so and it latches up. It uses a reg and had a 0.1uF ceramic on the end of the DIP pkg. That 0.1uF is also the cap for the reg output which is only 0.1" away.
It turns out that either 0.1uF was not enough or it wasn't located close enough, the Vdd/Vss pins on the PIC18F1320 are in the middle, 0.5" from the end of the chip. Sticking another 0.1uF on the underside of the board directly on the pins makes everything run nice and smooth!
A real feel good moment.
I finally found why this thing goes nuts. Even though I'm just driving a gate, no load on the FET, the pin and rail were seeing spikes to 6.5v or so and it latches up. It uses a reg and had a 0.1uF ceramic on the end of the DIP pkg. That 0.1uF is also the cap for the reg output which is only 0.1" away.
It turns out that either 0.1uF was not enough or it wasn't located close enough, the Vdd/Vss pins on the PIC18F1320 are in the middle, 0.5" from the end of the chip. Sticking another 0.1uF on the underside of the board directly on the pins makes everything run nice and smooth!
A real feel good moment.