Electronics Forum | Mon Feb 03 22:48:00 EST 2003 | vinesh
Hi all, We are using small CSPs (10x10mm) in one of our products which has a big ground pad in the center (7x7mm). The maximum voiding allowed on this big pad is also no greater than 25% which we are finding very hard to achieve. The centre pad ha
Electronics Forum | Sat Feb 26 20:44:46 EST 2005 | siverts
Some of the QFN's have/has? (sorry for the grammatics but I live in Sweden) a "ground pad" underneath the center of the body. Some of the manufactories have made a specification of how much solder fillet that needs to be covered on the center pad [f
Electronics Forum | Wed Jan 15 11:53:40 EST 2020 | avillaro2020
As far as the large thermal gradient I have on my thick and thermal heavy board, I've done quite a bit to minimize the gradient but not successful. it's like one pad is connected to a signal while the other pad is connected to ground, you can't bring
Electronics Forum | Wed Nov 10 02:20:07 EST 1999 | Marc
The padsfor large heat sinks are being designed on our boards with large copper ground planes surrounding them by our engineers. I am having great difficulty keeping the reflow temperature below 230 degrees in order for the temperature of the copper
Electronics Forum | Fri May 17 10:08:47 EDT 2013 | shrikant_borkar
HI, We are facing problem of Dry solder due to QFN Grounding Solder not Drain out in Via hole. also No drain hole on PCBs now we have 15k stock. which is leading to massive Rework. We have Tried by minimizing Ground Square apertures. but no Improvem
Electronics Forum | Fri Dec 03 18:01:56 EST 1999 | M Cox
Usually the alignment problem comes from pad design. The ground pad (largest) is too small. If that is the case (and even if it isn't) try placing a dot of SMT adhesive before placement (it will cure before reflow and hold the part in place). Goo
Electronics Forum | Tue Feb 08 19:45:14 EST 2005 | davef
Use multiple small stencil openings [15 thou square], where total area approximately 50% of total PCB ground pad. What's the problem?
Electronics Forum | Mon Mar 27 20:34:22 EST 2006 | ms
Thanks for the suggestion. The large ground pad appears as a single large pad on the component and PCB but we print a matrix of 28 small dots of paste to provide the solder for the joint. The inconsistent volume transfer can occur on any of the fo
Electronics Forum | Mon Sep 23 02:54:40 EDT 2013 | pradeep_selec
We are using Dpak package & I would like to know which is the best Aperture shape for DPAK, whether is there any problem if the Aperture of Ground pad is made of the same shape & size as the pad & what are the possible issues faced with it. Can I hav
Electronics Forum | Tue Oct 14 07:30:00 EDT 2014 | rob
For low voltage and current applications there are also some nice SMT conductive foam pads that come in on tape. http://www.gore.com/MungoBlobs/621/772/SMT_Grounding_Pads.pdf I think Laird also do something similar. We place them with no problem.
