Electronics Forum | Fri Mar 02 00:21:38 EST 2007 | AMS
Hello, I havea 0.4mm pitch TQFP with heat transfer pad on the bottom side of component. I will appreciate any suggestions with regards to: 1) stencil thickness (Rest of components on board are 0603 passives and few 40 mil pitch IC's) 2) Stencil
Electronics Forum | Thu Aug 08 13:05:45 EDT 2019 | horchak
What is your pad width? What is lead width? Is the part gang masked, or has masking between the pads? Pads plated or HASL, if HASL how thick? What is board thickness and size? Does it need to be fixtured for support thru out the process. Semi auto sc
Electronics Forum | Sun Sep 27 11:41:13 EDT 2009 | rajeshwara
We are using ST Demodulator QFP in our product which have exposed pad / heatsink from bottom side. Visually or in magnifier the solder joint or fillet looks good but if we touch up the pins with soldering guns , PCB works fine.
Electronics Forum | Thu Oct 01 08:34:50 EDT 2009 | davef
First, the reflow thermal recipe provided by your paste supplier is only a ball park guess. Beyond that, the temperature measured by thermocouples on your oven heaters are only loosely related the temperature of solder paste on your board. You need t
Electronics Forum | Wed Aug 07 17:55:33 EDT 2019 | slthomas
You should be well within area and aspect ration guidelines with that. Are you printing and placing close to center on the pads? Sometimes operators will "bump" the parts to center them on the pads if they're not placed correctly, and if they've bee
Electronics Forum | Tue Jul 01 13:35:49 EDT 2008 | realchunks
QFNs have pads on the bottom. LCCs have pads on the sides that are exposed on the bottom.
Electronics Forum | Wed Jul 19 01:20:17 EDT 2000 | Craig
Does anyone have any experience wave soldering TQFPs. Our R&D is wanting us to do this but we (production) are hesitant. I've found some recommended pad designs and solder theiving designs in a Philips app note "SMD Mounting Methods". The theory look
Electronics Forum | Fri Apr 16 17:44:12 EDT 2021 | dwl
I'm concerned by the solder spheres in the via on the first picture. Are these boards mis prints that got washed and printed again? To me it almost looks like someone washed the board, but left a lot of solder paste on it. The lack of flux prevents
Electronics Forum | Thu Oct 01 06:18:10 EDT 2009 | rajeshwara
METHOD OF VIA DESIGN AT EXPOSED PAD FOR QFN/QFP.
Electronics Forum | Fri Oct 30 08:24:12 EDT 2009 | rajeshwara
thnx davef & all With the help of all at last i solved the problem , The vias are not caped from bottom , so solder paste draining through the via to the floor which creates voids between IC ground pad and e-pad. Tnhx all again
