Electronics Forum: qfn toe (Page 1 of 2)

NXP QFN Solderability Wetting Problems, Kester

Electronics Forum | Thu Aug 10 07:29:43 EDT 2017 | stivais

How do you evaluate the soldering quality for those QFNs? X-Ray or AOI? For some QFNs (and other bottom termination components) it's not supposed to have solder fillets on toes. It's also noted in IPC-A-610 (Rev.F 8.3.13). Take a look at your QFN ch

How to improve the solder quality of QFN?

Electronics Forum | Fri Jul 15 13:58:32 EDT 2005 | seaK

Our production is putting QFN40 and QFN56 package on board. With 80% opening on terminal, 40% on thermal pad, we found QFN56 100% forming toe fillet, but it does not work out the same to QFN40. We suspect it's because of the weight of component.....

How to improve the solder quality of QFN?

Electronics Forum | Fri Jul 08 16:35:04 EDT 2005 | Jason Fullerton

"Whether or not you need a toe fillet depends on your application. We have high reliability products where we can't use a QFN over a certain size, regardless of toe fillet. We have other applications where we meet the thermal cycle requirements for a

How to improve the solder quality of QFN?

Electronics Forum | Wed Jul 06 14:36:05 EDT 2005 | Bob R.

The only way we can consistently get a toe fillet is to use a paste with an extremely active flux. We allow that paste on certain products, but discourage it's use because it's on the hairy edge of not meeting our lower limit in surface insulation r

IPC A-610 Moving from Rev E to Rev F

Electronics Forum | Tue Jul 04 14:50:52 EDT 2017 | dleeper

Thanks! good stuff. I am disappointed the IPC has put off updating QFN solder filet specs till rev H. It's a pet peeve of mine trying to argue with customers that a visible toe filet on a QFN is not necessary, and may not even be possible depending

QFN Side fillet

Electronics Forum | Mon Jul 22 02:13:31 EDT 2019 | jandon

some PQFN package configurations have no toe exposed or do not have a continous solderable surface on the exposed toe and a toe fillet will not form. (IPC-A-610F 8.3.13)

QFNs (LCCs)

Electronics Forum | Fri Dec 22 16:04:26 EST 2006 | mika

Hi, This Not so easy as one wuold think. Has the thermal pad of yours vias? How many? What's the via's dia? What is the pcb thickness? If the the pcb has a "ground layer" connected (vias) to the pcb thermal pad, it could sometimes be a little bit tri

How to improve the solder quality of QFN?

Electronics Forum | Wed Jul 06 12:25:55 EDT 2005 | HOSS

Bob, We have seen this same issue and haven't found a solution other than touching up to create a toe fillet. Luckily, it's a low volume product, for now. What have you done to combat this? Thanks.

QFN84 Solder Printing Issue (QFN with Inner LGA Pad)

Electronics Forum | Wed Nov 15 12:52:21 EST 2017 | georgetruitt

IMO – Look into nano-coatings for your stencil and radius all square apertures This should help out with solder paste releasing from the stencil helping with insufficient solder QFN LGA aperture design, try a stencil cut with a few different apertur

NXP QFN Solderability Wetting Problems, Kester

Electronics Forum | Thu Aug 10 11:24:18 EDT 2017 | dleeper

The exposed metallization on the sides of the QFN probably aren't tinned and therefore not expected to have solder wetted to them. If previous parts formed nice toe filets, it might just be that those parts were fresher and the exposed metal did not

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