Electronics Forum | Fri Sep 09 05:32:11 EDT 2016 | jasltd
Are your solder relief pads connected to anything in terms of ground planes that would increase the thermal load or are they floating copper? I take it your talking about wave solder relief pads?
Electronics Forum | Wed Dec 11 07:05:28 EST 2019 | ameenullakhan
Hi, Below may help you out. per IPC 7093 ( Design and assembly Process Implementation for Bottom Termination Components ),Clause 6.1.5.3 voids on thermal pad up to 50% does not result in loss of thermal performance. Since the void criteria is
Electronics Forum | Tue Apr 10 08:37:36 EDT 2018 | davef
Hi Steve ... I found nothing in the manufacturers "paper" to help. Comments are: * I agree. No blobs. Solder on the thermal pad should me minimized. Too much solder will float the component. Old timers used to talk about 50-80% coverage. * If you'
Electronics Forum | Mon Dec 06 14:44:41 EST 2021 | dwl
1 to 1 stencil aperture to pad should be fine on the gull leads, and yield 100% coverage with leaded solder. The thermal pad is going to be a challenge though, if you truly need 100% coverage. There will be out gassing from the flux and this will nee
Electronics Forum | Fri Aug 03 22:36:28 EDT 2001 | mugen
We used Thermal Pads, made of black rubbery material, and sticky on both sides (like x2 side tape), intent is to place in between, BGA/QFP and the PCB board, and reduce the air-gap flow between, the PCB to SMD... air-gap will permit air flow, that i
Electronics Forum | Wed Jul 15 18:04:43 EDT 2015 | mikekeens
If it is important to have vias within thermal pads to help dissipate heat i would recommend using solder mask to stop the solder from wicking down the holes and resulting in insufficient solder. Some further info can be found here:- http://www.surf
Electronics Forum | Thu Jul 20 23:41:55 EDT 2017 | heros_electronics
Below is an email that I copy and pasted from my customer's engineer about his concerns with the issue of the chips not reflowing (which is why I was asking about X-ray the chips to make sure they reflowed): Can you let me know your thoughts on his
Electronics Forum | Thu Oct 26 10:29:03 EDT 2006 | Mike
First, Voiding under thermal pad is unavoidable(pardon the pun), unless you can find a way to add sufficient amount of solder paste to cover the area, and match that solder volume on your terminal leads. I build HVM qty's of "QFN" components w/ therm
Electronics Forum | Fri Aug 25 09:15:43 EDT 2006 | russ
We use a single large pad on board and reduce stencil aperture 50%. If you mask/reduce the thermal pad the solder will not wet out to edges and you will still see the part standoff with the open joints. the purpose of reduction is to wet the paste
Electronics Forum | Fri Nov 09 10:37:38 EST 2007 | devajj
We have started using QFN packages in large volume and are having problems with no-solders. We are using 6mil stencil with 1x1 paste print to pad. These also have thermal pads with thru vias that we reduce the stencil aperture by 1/4. Board also ha
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