These two are identical, except the one on the left has a dead short from tab to leftmost pin; the one on the right is fine.

What is it? Presumably a power FET of some kind (5103 P-ch MOSFET??), but I don't even recognize the logo.

Any/all help welcome, thanks!

Hi.

I'm reasonably sure that's the logo for what was Harris Semiconductors, which was bought by Intersil quite a while ago. How old is the device they're in, and what is it?

pca

Edit: Yes, definitely Harris

OK, I think this is the same thing from what I can see. It would appear to be a P-channel logic level power FET.

Nothing particularly special about it, you can probably find an alternative from IR or someone like that. The original was definitely Harris, then I think Fairchild, but I can't find a datasheet for either.

pca

The IRF9540LPbF is a good replacement, the same or better performance with the same pinout. It's in a D2PAK package, which is slightly larger than the TO-252 one, but would probably fit with a little care.

pca

Peachy, thanks!

This is inside a Ford automobile Engine Control Unit (ECU). The original (left side one) is supposed to be controlling the O2 sensor heater, but has died a horrid death at some point. Not mine, but just doing a favour for my local auto mechanic.

We dug through his extensive collection of dead ECUs, and found one with four similar 5103 parts onboard. I've now used a heat gun to liberate those, and used one of them to replace the dead one on the original ECU.

We'll find out on Friday whether that's all that needed fixing (or not!).

Cheers

I fixed my ECU on my old Jeep for about $2.50 worth of capacitors earlier this year. Worked great. Hope your fix works as well.

Good job on the Jeep, John!