Author Options:

Can any one identify this component? Answered

I find it a lot on sound enabled electronics PCBs. It is this black circle on the board.



Best Answer 8 years ago

What this is is COB - which stands for Chip-On-Board. Instead of buying the packaged chip (black oblong with silver legs) they buy just the bare silicon chip which has been specially prepared with solder blobs on the contacts on its surface. Then they mount this bare silicon directly to the PCB by positioning it over the pads and warming it up so that the solder blobs melt anf the chip is fixed to the pcb. This is sometimes called 'flip-chip' because the chip is mounted face-down onto the pcb. But the silicon is fragile and so they cover it with a blob of black goo to protect it. This method is used because it is compact and very cheap - so it can be used in greetings cards for example. But it is also used on the back of LCDs for their driver chips too.

zem, I was able to auto correct for lighting, and play a couple of games to improve the resolution, but it's still kinda blurry. (using a webcam?) anyway, it looks like they may have covered an ic with a blob of epoxy. I originally though tit might be a speaker, and it may still be, (or the underside of one) but from the pic it looks like some from of obscuration trick, either to avoid someone finding they've impinged on someone else's copyrights or to avoid competition getting hold of a part number for something that can't be copyrighted it could also be the underside of a component that needed to be mounted using epoxy for vibration isolation...not sure Pic of the other side please.

Hey, sorry the quality is not very good, cell phone pictures... Here is the picture of the other side, the resistor on top at the very edge is right over the black blob.


I think that either karnuvap and/or Jayefuu accurately answered your question already.

I agree with the others - the black blob is in effect a case for the chip underneath. It's a microprocessor / memory chip. L


Underneath it is a tiny microchip with some software embedded in it. The actual black bit is just some plastic to protect it. (I think)

Very good!...might quite well be an Eprom. black goo to prevent accidental wipe of IC contents thru the erase window

Ah! Thank you guys.