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I am trying to design a board that has a surface mount connector. I was shown a picture of an example board that has vias on the pads of the connector. I don't believe the via is for connecting to a layer necessarily. Meaning I was told that they were used for strengthening the mechanical structure near the connector so that it would be more difficult to yank off when pulling and pushing in the plug.

Has anyone ever heard of this? I believe I have heard of putting a plugged via right next to a mechanical pad so that the board is stronger there. But I'm not sure what the implications are for putting a via on the pad? I've been searching the web and I can't find much. Maybe I just don't know the proper terminology for this application.

So is there a standard for adding strength to surface mount connectors? Is putting a via on the pad a good or bad practice, other than expense? Does putting a via directly next to the pad help?

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That's a new one on me! There are other reasons for putting a via in the pad, but strengthening a connector is a new one.

The weakest part of an SMD pad is that the copper could delaminate from the fiberglass, and lift off the PCB itself. Anything you could do to prevent that would help, including making the pad larger or putting a via in the pad itself.

But you have to be careful, since putting a via in the pad can cause other issues. The first problem is that it might make the pads not flat enough, so a connector pin won't make good contact with the pad and thus not get soldered well. The second issue is that the solder could get wicked down the via and leave nothing left for the connector pin. This isn't a big issue if you are hand soldering, but can be a problem when doing it with automation.

Honestly, if connector strength is an issue then seriously consider going to a through-hole connector or some type of connector that gets strength from some other means. Maybe a connector that gets bolted to the chassis itself (and stress on the PCB is minimal). Or even a different connector entirely.

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    \$\begingroup\$ +1, my setiments too. A via completely filled with solder might add some strength, but overall could make things worse as you say and because you loose some surface area of the pad. Your 4th paragraph is right on. If this part is a problem, find one that isn't. Connectors are about the only things I use in thru-hole style nowadays. \$\endgroup\$ – Olin Lathrop Jul 17 '13 at 15:34
  • \$\begingroup\$ I believe you are correct in assuming that the via will help keep the pad from delaminating. I also believe that this is what the original poster meant by "strengthening the mechanical structure": Making sure you didn't yank the pad up with the connector when you pulled. The plated via should help this, I believe, as you said. \$\endgroup\$ – scld Jul 17 '13 at 16:26
  • \$\begingroup\$ Thank you for the info David. The connector choice is not under my control unfortunately. But overall this is the information I was looking for. \$\endgroup\$ – AntMan Jul 17 '13 at 17:06

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