Electronics Forum | Thu Mar 29 02:46:25 EDT 2012 | johndoe0222
My company is doing a project with a lot of QFN. The question that we are not sure is how to properly solder a QFN on a PCB. QA says The alignment tab on the side of the QFN should have a physical solder from the board, like a leaded chip. After refl
Electronics Forum | Thu Nov 15 09:29:03 EST 2007 | jaimebc
Just to add to the subject, we experienced insufficient solder on our QFN's at our prototype level. To correct it, we went to a 5 mil stencil, 20% reduction on QFN pertures and used QFN's with solder bumps on the pads. We had great results using thi
Electronics Forum | Thu Mar 29 10:28:40 EDT 2012 | thanh
Your QA don't know nothing about QFN. look at Bill Axler post, he was 100% corrected.
Electronics Forum | Fri Apr 06 11:01:34 EDT 2012 | umairzameer
Agree with Reese with my experience with QFN parts it is the reflow.
Electronics Forum | Thu Apr 05 08:21:52 EDT 2012 | rway
Yes, but no guarantee of solderability. This just puts more paste on the pads. From my experience, unsoldered QFN parts are not due to lack of solder, but reflow.
Electronics Forum | Wed Nov 14 01:00:20 EST 2007 | reypal
recently, we also have problem with QFN around 3% defect related to soldering. from the cross section it turns out to be solder crack. it could be the paste volume on the center pad is too much causing QFN to float that eventually will cause crack on
Electronics Forum | Mon Nov 19 14:23:32 EST 2007 | realchunks
BINGO! Now that's engineering!
Electronics Forum | Wed Apr 04 13:40:22 EDT 2012 | rway
I agree, the only way to "truly" inspect a QFN is with an X-ray. But this might be over-kill for him. He asked about soldering, not inspection. We use QFN's regularly and you can inspect these parts from the side to see if they are soldered. Unfo
Electronics Forum | Mon Nov 12 09:13:50 EST 2007 | russ
Chunks is right, reduce center pad by 50% print the signal pads at 1:1. this will ensure you solder QFNs fine regardless of the actual part. If you are not printing then it is process capability issue and has nothing to do with QFN but rathjer small
