Electronics Forum | Thu Apr 01 12:31:39 EST 2004 | russ
one more thought on this, When these boards are built new do we not have solder paste on the ground pad and then reflow? Has this caused any misregistration for you? I am assuming that you are not pasting the leads with the ground pad correct? I
Electronics Forum | Wed Sep 12 22:57:02 EDT 2007 | lito_visaya
Anyone, We are an electronic assembly contractor and one of our customer requires a 100% solder coverage on pads for their products. We are using flex pcb and we mount only one component (LED for backlight application). The solder paste we are u
Electronics Forum | Mon Jun 14 10:23:53 EDT 2010 | pcrane
I have CCA that has a SN100C HASL coating that I am wave soldering with SbPb. I have mounting pad areas on the CCA that are masked with a pallet during reflow so they are not exposed to the solder. The mounting pads are turning gray in some areas of
Electronics Forum | Thu Jul 19 21:55:14 EDT 2001 | davef
You're correct, but you need to take it a little bit further. Installed correctly, ExposedPad� TSSOP IC packages significantly increase the thermal efficiency of power constrained standard TSSOP packages. This can increase heat dissipation by as mu
Electronics Forum | Thu Mar 30 08:48:37 EST 2006 | russ
So you have solder balls at the outer edge of the part right where the pad goes underneath? If so you just have too much solder but I wouldn't worry about them. the solder usually does not wet to the edges of these parts because of the exposed copp
Electronics Forum | Thu Aug 02 17:27:54 EDT 2007 | jmelson
This process is going to make conventional rework, and most mods and ECOs impossible. You might be able to make some changes by patching a component across the exposed pads, but most of the circuitry will be buried. You could, of course, make speci
Electronics Forum | Tue Dec 28 03:54:50 EST 2010 | riscy00
Hi Has anyone has thermal capacitance model for QFN (9x9) package with exposed pad 7 x 7 (or 6 x 6). Ideally between junction and case, junction case and board (JESD51-7 or similar). I wish to do transient with spice, to established how long it tak
Electronics Forum | Mon Sep 17 05:48:10 EDT 2012 | stivais
Hi Ben, Yes, this could be the reason but have you ever seen solderability issues for (new) boards with LF-HAL surface finish? I have seen this only if there are surface finish quality issues for bare boards (exposed copper etc.). In this case we di
Electronics Forum | Wed May 10 00:27:46 EDT 2006 | Chris
Russ, By a longer profile you mean a more even slope across the entire profile. Unfortunately I only have a 5 zone oven that is fairly short. How many heated zones are you using? Did you shrink the 0402 pad design and leave less pad exposed out a
Electronics Forum | Thu Apr 25 18:32:25 EDT 2002 | Shawn
What he is talking about when he said "foil" is the top and bottom side of the board has a layer that is like a ground plane with no solder resist covering it. It is etched out around the pads that no not need a connection and have a small bride or t
