Electronics Forum | Wed Jul 25 10:57:08 EDT 2007 | cecil
Our board layout folks are currently designing a PWB using a 132 QFN. The component is .5mm pitch with .35mm square pads. The component manufacturer recommends the following footprint: .4mm square land .3mm square solder resist 1.why do they spec
Electronics Forum | Mon Mar 11 06:49:42 EDT 2019 | SMTA-Bob
You problem will be related to the part type or the design. Standard 40 or 100 pin QFN or LGA parts are not going to drop due to weight as they are just a few grams. If you send a photo of the PCB pad footprint and the component separately I may be a
Electronics Forum | Fri Apr 06 10:43:57 EDT 2007 | flipit
Hi, Anyone seeing difficulty is soldering MLFs or QFN with lead free solder? I have an MLF with 3 rows of pads on each of the 4 sides of the part and then the large center ground plane in the middle. The part is 20 mil pitch. Had good luck with l
Electronics Forum | Fri Dec 01 12:56:33 EST 2017 | emeto
It seems that it will work with 5 mil stencil. To be safe use 4 mil if the rest of the design allows it. 10x20mil apertures for both rows. If you have bigger footprint in the corners, make bigger apertures there. For the ground plane, I would use ver
Electronics Forum | Wed Mar 27 07:01:26 EDT 2019 | charliedci
200uM seems high. I say this because typically our solder stencils in this application are between 80uM and 100uM thick which would leave the component height less than that after reflow. However if your not experiencing any shorting between pads I w
Electronics Forum | Wed Jul 30 00:47:10 EDT 2014 | matusov
Hello gurus, I am a hardware designer with a small company. We are about to send a new PCB for fabrication. This board uses dozens of tiny QFN, DFN, and similar packages. As a final check I have been going through the datasheets of all these parts t
Electronics Forum | Sat Apr 07 01:15:45 EDT 2007 | Haris
Hi I dont think there is a stencil problem or a printing one but i think you should check you paste specification regarding 20 mil pitch i.e. its ball size in microns so that you know Is that paste can be use for this type of components or not. Secon
Electronics Forum | Mon Oct 07 22:06:43 EDT 2013 | action_101
I successfully inspect solder on plcc's with angled cameras on the yestech we have. In the past I have successfully inspected for solder with angled cameras on mirtec machines for both plcc's and qfn's. Other than inspecting solder on those two types
Electronics Forum | Thu Mar 30 09:32:54 EST 2006 | russ
Not arguing dan, but are you positive that they are not copper? anyway, what is happening is as the parts sucks down onto the board from reflow the extra paste is notnecessarily sqeezed out but it has no place to go. So it will form this ball on th
Electronics Forum | Wed Mar 04 08:21:42 EST 2009 | rgduval
It seems familiar, but nothing that I've actually experienced. I've read some articles about tin-whiskering in lead-free solder. I think NASA has some pretty good analysis (or, at least they did a couple of years ago). The summary is that without
