SMD Identification

Anybody have any advice on identifying SMD components? The magic smoke escaped from one on a board I’ve got here. Trying to avoid sending it back to the manufacturer. I’ve got another new board here that I can cross-reference.

Number on the chip looks to be 618W, unless I’m reading it upside down…

I think it is actually a 618V (with a bad/modified/double printed legend). And is probably a FMMT618 transistor.
I found that by a simple google of smd 618v, There are a lot of very spammy/ad-tastic ‘SMD Identification’ sites out there, but I generally find Google with a part number + smd in the search term is the best way to start. Searching for numbers without the suffix can also be useful, they often get varied for the same basic component between manufacturer or package type.

For myself, I’d be tracing the surrounding circuitry (eg; is it wired as expected for a transistor) to double check… and remember that the problem may not be confined to this one component; even if it is the only one that shows damage.


What board is it? That might help identifying the transistor or dual diode…


It’s a Tele Radio brand radio receiver we use on some of our equipment. Proprietary and no chance of a schematic, which is understandable.

Thank you, I’ll check into that transistor when I get a chance. I’d tried just “SMD 618”, but had gotten overwhelmed by the results and wasn’t even seeing anything that for that physical layout. I’ll definitely poke at the surrounding circuit some more and weigh my potions before sticking a questionable chip in that spot.