Electronics Forum | Tue Apr 28 07:45:07 EDT 2009 | davef
When using high tin solder, doesn't proper specing to avoid the effects of tin whiskers become at least as large an issue as proper specing for defect-free wave solder processing?
Electronics Forum | Wed Apr 29 04:57:08 EDT 2009 | davepick
It depends on the application what will be considered the biggest issue to avoid (production or longterm reliability). Tin Whiskers are bit of an unknown quantity - but a more realistic problem could be dendritic growth / electromigration forming sho
Electronics Forum | Wed Sep 29 09:29:47 EDT 2010 | swag
Take a few parts from the reel and look close at the parts to make sure the bottom surface of the leads is below the bottom surface of the body.
Electronics Forum | Mon Jun 30 08:55:31 EDT 2008 | davef
It will be tough to find a dimensional thickness specification for HASL. IPC-6012 Table 3-2, line "Fused tin-lead or solder coat - Coverage and Solderable" states the requirement that there has to be complete coverage of solder on the land, and it mu
Electronics Forum | Thu Apr 30 05:54:41 EDT 2009 | davepick
Michael, There are so many factors involved that mean a definitive number is extremely difficult - if not possible. I recommend you speak with Tony Wilson. He has been in the industry for over 25 years and reccently done PhD work on modeling failure
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 | Wed Jul 30 23:40:45 EDT 2014 | matusov
Yes, but I have seen designs where the whole row > of leads has no mask(which is also a NSMD) Apparently I might have to do just that for some parts. We have a few parts with 0.2 mm pads at 0.35 mm pitch. Our PCB shop says that they need at least
Electronics Forum | Wed Jul 30 11:55:09 EDT 2014 | matusov
I would consider to have mask in between the leads and have it open a little bit more than the copper Thank you. That is exactly what the NSMD pad is!
Electronics Forum | Wed Aug 27 15:50:11 EDT 2014 | smtdoug
If at all possible, you definately want solder mask defined pads. Without it, you will struggle with solder bridging. This is especially important if you have a larger size board.
Electronics Forum | Wed Jul 30 11:36:31 EDT 2014 | emeto
About the pads shape - you can do rectangular or oblong. For stencil design oblong is better for small pads(0.2mm) because it will give better release, so having this thought in mind you should probably design oblong shape and then print make paste a
