Electronics Forum | Thu Aug 21 08:33:09 EDT 2008 | davef
There is no standard as such. It's easy to see why. It's too complicated and has such a small payoff. Standoff is comprised of: * Package height * Solder thickness between the pad and the component lead * Delta of pad thickness and solder mask For p
Electronics Forum | Wed Oct 03 09:56:51 EDT 2001 | Claude Tremblay
Hello everyone We have a QFP-308 (0.20" pitch)on a board and we have a lot of opens after reflow. We checked our profil by installing thermocouples on the pads of the component and everythings seems OK. We checked the coplanarity of the leads and it
Electronics Forum | Wed Apr 11 20:58:12 EDT 2018 | jacobidiego
YES to the first question in some points of the board. Bulky, to the second question when it is not in short. What you say about the PAD height, helped me to understand why the SPI shows weird values for other measurements. I am currently doing test
Electronics Forum | Mon Jul 24 10:15:23 EDT 2006 | slthomas
Set-down height to low, iow, parts getting squashed too deeply into the paste. No mask between pads on fine pitch. Pads too wide for the pitch.
Electronics Forum | Tue Jun 13 21:57:01 EDT 2000 | Dave F
Todd: You say: "... solder masking between the lands of fine pitch components can cause stenciling problems and or manufacturing problems." I say: Fine pitch components without solder masking between the lands can cause stenciling problems and o
Electronics Forum | Tue Aug 17 14:34:27 EDT 2010 | davef
Comments are: * Too much paste ... reduce it more. * Do not let a traces run between small discrete pads or the heat of reflow will pull a ball to the trace, we can repeat this. * Change the placement height on chip parts to reduce solder spread / mu
Electronics Forum | Fri Dec 01 14:40:02 EST 2017 | emeto
Very interesting pictures. It shows paste height of 200um - which is at lest 6mil stencil deposit. That on the other hand posts another question. Can you measure the ground pad level in relation to the solder mask level with the SPI? I had assemblies
Electronics Forum | Wed Oct 24 14:06:37 EDT 2001 | mparker
If you let your design team leave things up to chance, chances are something will go wrong. You are right to want to take control rather than be lead down an undesirable path by the fab house. Various masks serve certain desirable purposes. You need
Electronics Forum | Thu Jun 15 12:57:12 EDT 2000 | Dave F
0.0006" LT Total pad height = Thickness of ( Copper pad + OSP ) = 0.0014" + 0.00000157" = ~0.0014" (You must be using an organic solderability preservative (OSP) or Electroless Nickel immersion gold (ENIG) because 0.003" tin/lead or white tin would
Electronics Forum | Wed Sep 18 12:31:16 EDT 2002 | dragonslayr
My suggestion is to conduct a Design For Manufacturing (DFM)study on the assembly in question. Pay particular attention to the pad sizes, component lead dimensions and satisfy yourself that those two factors are correct. Given that pads match compone
