So I am working on a soft-switch for my robot project. It involves a PICAXE and a P-Chan MOSFET used to switch the high-side of my main power supply based on a user button press or the RaspberryPi sending a power-down signal. I would like to have plenty of head-room in current capacity and I have two options on hand:
- One is giant-sized SMT MOSFETs that are rated to 25A or something stupid high like that. I don't think I could reasonably even make traces to handle that but it would run most any project I have without a sweat.
- The other is an SOT-23 package that is rated to 3.5A peak.
What I thought would be an ideal match is to parallel two of the smaller ones for 7A combined and that would be 75% headroom over what my peak draw is right now.
My question is.... is it really that simple? Can you just parallel the MOSFETs and drive the two gates the same? I know often times that does not work out as intended as one component is ever so slightly different and ends up taking on all the load, fails and then the next in line repeats it's demise. Reading some posting seems to suggest that this is not the case with MOSFETs but I wanted to ask directly before I start working up a PCB.