Electronics Forum | Fri Dec 27 14:11:18 EST 2002 | cnotebaert
We have placed these parts. I have not had problems with them but when I designed the stencil we reduced the app for the large thermal by 20% to reduce the chance of problems like your having. If the balls are close (.040-.050" or
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.
Electronics Forum | Mon Apr 16 16:24:20 EDT 2018 | slthomas
Amazingly enough, every one of these held fast where we placed them with a paste brick sized 1:1 with the thermal pad, no sectioning. Yes, there were voids, but we can live with that in this application.
Electronics Forum | Tue Apr 10 08:37:36 EDT 2018 | davef
Hi Steve ... I found nothing in the manufacturers "paper" to help. Comments are: * I agree. No blobs. Solder on the thermal pad should me minimized. Too much solder will float the component. Old timers used to talk about 50-80% coverage. * If you'
Electronics Forum | Fri Sep 17 13:24:27 EDT 2004 | Bob R.
I also agree with Russ - we use step stencils when we have to but generally try to avoid them because the print isn't as consistent as with a single thickness stencil. Many of our products are for harsh environments so we do a lot of thermal cycle a
Electronics Forum | Mon Apr 09 12:52:00 EDT 2018 | slthomas
We are about to do a second iteration of something we struggled mightily with last time and I'm hoping to at least make a step in the right direction. There are 12 of these parts on the board and virtually all of them required removal and replacemen
Electronics Forum | Thu Feb 27 08:59:15 EST 2020 | spoiltforchoice
In both cases, it will depend on storage conditions, unless you do something horrible to them (or as previously mentioned, wash them) months & months. For boards we put through SMT and then stash for THT loading in smaller qty's I don't think we've e
Electronics Forum | Thu Dec 21 15:34:48 EST 2006 | russ
we are reducing the thermal pad stencil apertures by 40% on these with great results Russ
Electronics Forum | Thu Mar 09 04:04:48 EST 2006 | dougs
one point to remember is to have a large stencil reduction on the thermal pad, you need to reduce the solder volume by about 35%, if you don't you risk the solder from the thermal pad shorting out the other leads or the solder volume causing the comp
Electronics Forum | Thu Sep 01 09:05:47 EDT 2005 | russ
Thermal pads located underneath leadless devices require a 50% reduction in the stencil aperture.
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