Electronics Forum | Tue Nov 13 20:29:03 EST 2007 | grantp
Hi, What size via's are you guys seeing, as the ones in our products are incredibly tiny, and via's are very small now days. The via's on the boards we have are dramatically smaller than the pad on an 0402. Grant
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
Electronics Forum | Mon Mar 17 18:23:43 EDT 2008 | swag
Thanks all for the replies. Chunks has hit the nail on the head as the distance between pads is so little that the boardhouse was unable to apply soldermask. We are in the process of having the pads resized to allow for soldermask. Hopefully this
Electronics Forum | Thu Mar 20 08:45:02 EDT 2008 | davef
Common methods use to protect pads from solder splatter are: * No residue Kapton tape * Nonionic solder mask
Electronics Forum | Mon Aug 25 10:36:05 EDT 2008 | davef
Yes, it's peculiar that the layout of this board is so disorganized * Pads are not round, uniform, or the same size * Exposed traces have different thickness
Electronics Forum | Wed Oct 01 04:43:36 EDT 2008 | omid_juve
we need a soldering nozzle for this package that can be placed by the rework machine on a pads of this qfp (to make the pads planar) and then send a hot air and after the solder joint melt stop the hot air and pull up the nozzle do we have such mach
Electronics Forum | Thu Nov 13 07:57:36 EST 2008 | alien
What type of solder wick do you use for cleaning up QFP pads after desoldering ? Many brands only wick well at the end, but not when laid flat over the pads. Swisstone brand (made in US) works best for me, but the suppliers seems to play hard to ge
Electronics Forum | Mon Dec 08 14:11:14 EST 2008 | comatose
We run a bunch of .5mm qfn on a GSM1 with a 2.6mil camera, from 16 pad to 100 pad. Works like a charm. We call them a PLCC.
Electronics Forum | Tue Dec 23 14:45:06 EST 2008 | comatose
One thing that helps is to divide large pads into a series of smaller pads. This prevents the scooping you're talking about.
Electronics Forum | Tue Jan 20 17:12:25 EST 2009 | smt_guy
Thanks guys. They are seen on some of the pads too. What will happen if I continue to solder them and I got a good solder joint formation? Will the pad continue to erode or corode in due time? or the solder that will recoat its surface will prevent
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