Electronics Forum: thermal pad (Page 10 of 49)

Void under QFN TI LMZ20502SILT

Electronics Forum | Tue Aug 14 08:19:45 EDT 2018 | buckcho

Hello, other colleagues gave you valid ideas. I found it helpful if i reduce the size of the cooling openings. I would suggest making the four big square into very small many diamonds. This would maybe decrease your voiding with 2-4 percent. Btw how

CSP No clean residue

Electronics Forum | Mon Dec 06 12:27:01 EST 2004 | Scott B

We are currently reviewing a design which has a leadless chip scale package with a solder thermal pad on the underside. The application notes for the device specify use of a no-clean solder paste as the gap under the device will prevent cleaning. Is

How to improve the solder quality of QFN?

Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK

Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....

Solder balls under LLP

Electronics Forum | Wed Aug 31 12:49:04 EDT 2005 | kmeline

I have been having the same problem with the LLP. I have three stencil I have done reduction on. The first I went by the manufacturing recommendations. The last two I have done more reducing for the thermal pad. The last one was at a 20% reduction an

Can you wave solder this part

Electronics Forum | Thu Aug 24 03:20:36 EDT 2006 | aj

we had problems with fillets and shifting aswell,but the recommended print aperture is reduce thermal pad by 35% and offset the lead print by 3thou...i.e. 3thou over hang on outer edge of lead which also moves the paste 3thou in from the inner edge .

QFN - FCT failed after reflow

Electronics Forum | Wed Feb 07 09:37:48 EST 2007 | billyd

Had the very same thing happen the first time we used the small QFNs. The aperture for the thermal pad in the center needs to be cut in a grid form, either squares (with around a 10 mil spacing between openings) or circles, like a BGA pattern. Too mu

What is the QFN or Device Voiding Levels Needed for Automotive Industry for Power Devices for Electric Vehicles?

Electronics Forum | Wed Mar 15 12:39:24 EDT 2017 | cyber_wolf

Customer precedes standard, but customer must be educated and informed on what is achievable with their design and what is accepted as industry standard practice. My guess is that the negative effect of those voids is negligible. {Voids at the sold

Nordic aQFN73 stencil design

Electronics Forum | Wed Jul 18 17:09:45 EDT 2018 | slthomas

Update - next run started out horribly so went to another stencil design. Reduced thermal pad coverage by about 40% with 4 panes, with cutouts to avoid the vias. Worked like a charm for 10 boards (90 parts). I think we're finally on to something.

How to reduce solder joint voids of LED without using vacuum reflow?

Electronics Forum | Tue May 07 10:36:38 EDT 2019 | slthomas

Probably just means you started out with an optimal profile. I suspect that not everyone does. ;) It seems like we did have some luck with profile adjustments in one instance with some QFN's with a large thermal pad. Like I said, though, the profi

D-pak end joint wetting

Electronics Forum | Sun Apr 19 12:54:39 EDT 2020 | davef

A-620G doesn't require 100% wetting to the thermal pad. It requires 100% wetting to the land in the end-joint area. The end joint is the portion of the solder connection that is at the top [or bottom] of the connection. Look at 7.1.3 Solder Joint A

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