Pin config for IRF9540N


New Member

I'm new to electronics and I'm trying to build Jurjen Kranenborgs two-wire serial network.

I've search everywhere and checked out the datasheets but haven't been able to work out the pins for the IRF9540N MosFET. The datasheets show that looking at the device from the front, the pins are 1,2,3 from left to right but doesn't say which is the drain, source and ground.

Is there a standard for T0-220 mosFETs?



It DOES say on the IR Data Sheet I looked at.
Look at last page section "Package Outline"
Look at the picture TO220AB, then see to the right is a little listing.
Seek and ye shall find.......

PS. And you'll notice that the Tab is marked 4 , so don't forget that it ain't isolated when stuffing into breadboard.
Last edited:


New Member
Hi Dippy,

I must have looked at that datasheet ten times and didn't see that bit. I could have the circuit up and running by now if I had seen that a couple of hours ago.

Thanks for the quick reply.


No probs.
Data Sheet could have been better written, but the author is probably only on £50K a year so what can we expect.