Electronics Forum | Wed Sep 15 04:12:11 EDT 2010 | headlad
We had a similar problem so we shrunk the thermal and extended the pads. This allowed us to ensure solder resist was applied to the track in between. It fixed our problem.
Electronics Forum | Thu Sep 16 08:47:39 EDT 2010 | headlad
I extended the pads to help ensure the component locates correctly and to allow for easier re-work should problems occur. I reduced the thermal by 5% but you may want to speak to your fabricator and ask what they require to ensure that the resist is
Electronics Forum | Tue Sep 14 17:06:25 EDT 2010 | asksmt
Hi All, I have designed 4 Layer PCB with one 28 pin QFN PKG. I have got complaint from Production that the pads which connected to thermal pads (gnd) thru trace is bridging with solder and because of this bridge, pins are not getting soldered prope
Electronics Forum | Wed Sep 15 10:59:12 EDT 2010 | asksmt
Thanks for the valueable feedback, I have two questions 1. why do you have to extend the pad size ? is it okay if i keep pad size 2. I am currently using thermal pad size recommended in datasheet max value 4.2mm x 4.2mm, how much should i shrink
Electronics Forum | Thu Sep 16 17:56:48 EDT 2010 | asksmt
Ok Thanks, i have reduced thermal pad size by 4.5 mils on top and bottom part of this footprint where the problem was occuring, so now the clearance between thermal pad and lead pads are 12 mils instead of 7.5 mils on two sides. (i kept the signal pa
Electronics Forum | Thu Oct 15 11:04:28 EDT 2009 | spitkis2
Thanks Jim. Pressing the QFN into paste was what I thought of, just wasn't sure if it would cause solder paste to be pressed outside the pad area and possibly bridge with an adjacent pad. Do you recall the ratio of paste coverage to the pad area?
Electronics Forum | Wed Nov 28 20:03:36 EST 2007 | chs
Hi, Thanks for the info. You mentioned about TQFP, how about QFN, which is leadless and one sided package compared to TQFP ? Actually, we are component manufacturer. Recently we have multiple customer come back with issue of electrical failure on par
Electronics Forum | Wed Nov 28 16:08:38 EST 2007 | jmelson
I've been using Xilinx TQFP's in the 44 and 144 lead sizes with no trouble. I don't even bake them before reflow and have never had any problem. The Xilinx parts are certainly NOT sensitive, I could not break one with my bare hands if I tried (I ha
Electronics Forum | Thu Mar 15 18:15:28 EDT 2018 | maustin
The 740 has been a great machine for us. We've been able to reliably load components as small as 0603 (we've not tried 0402, but I believe with a special nozzle adaptor, you can get it to work) and place a 7x7 56 pin QFN with 0.4mm pin pitch with hi
Electronics Forum | Mon Oct 23 06:50:06 EDT 2017 | spoiltforchoice
For package shapes/names I would recommend using manufacturer names. This is much safer than coming up with descriptive names like QFN32_5x5 as there are multiple 5mm 32Pin QFN shapes even when pitch is the same, this makes it safer to use a name in
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