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I'm creating a footprint, in Eagle, for a USB-C connector. The part has 16 SMD pads and 16 duplicate through-hole pins.

The pins are very close to each other and the specs in the datasheet have annular rings that are too narrow for my PCB manufacturer. If I let the DRC grow their width to something acceptable for the manufacturer, they become too close to each other. I don't need to use those PTH pins since I'm only interested in the SMD pads.

I was thinking that I should just create (un-plated) holes instead of vias for those pins. The pins would just end up "floating" in those holes instead of being soldered in place - i.e. they wouldn't be electrically connected to anything. They don't seem to provide any structural role since the part has sturdy tabs that keep it in place.

Can you think of any issues with doing this? I could also just create a cutout around the group of PTH pins, but I'm trying to avoid cutouts and stick with drill hits for ease of manufacturing.

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  • \$\begingroup\$ Using right part for the job would be a good idea \$\endgroup\$
    – Maple
    Jun 2, 2020 at 2:50
  • \$\begingroup\$ How do you have unused pins on a USB-C connector? \$\endgroup\$
    – DKNguyen
    Jun 2, 2020 at 3:12
  • \$\begingroup\$ "part has 16 SMD pads and 16 duplicate through-hole pins." - exactly which part is it? \$\endgroup\$
    – Bruce Abbott
    Jun 2, 2020 at 7:02
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    \$\begingroup\$ Could you post a picture of the footprint \$\endgroup\$
    – Tom Carpenter
    Jun 2, 2020 at 10:29

1 Answer 1

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If the connector you are talking about is what I think it is, then the "16 duplicate through-hole pins" are not duplicate pins at all - they are the B-side of the USB-C connector. Though in theory there should only be 12 of each.

Because it's a reversible connector, you will have two complete sets of pins, one set for the top side (the SMD pads), and one set for the bottom side (the pins). You must connect both sides up on your device, otherwise the connector will only work when both ends of the cable are plugged in in the correct orientation.

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  • \$\begingroup\$ Oops, yes, that makes sense that the A and B pins both need to be used. (And yes, there are 12 not 16). I guess the fact that the A pins are smd pads and the B pins are through-hole threw me off - I was thinking they were alternatives to each other. \$\endgroup\$
    – RobD
    Jun 3, 2020 at 3:49
  • \$\begingroup\$ Since we're being specific (I was trying to make it a general question), the issue I'm having with the PTH pins is that they are .4mm diameter holes and .6mm diameter with the plating. That leaves an annulae ring of only .1mm which is too small for OSHPark (they need .127mm, which would cause the plates holes to bump into each other.) This is the footprint: dropbox.com/s/x3eu2n4od2agrdj/KUSBX-SMTTH-CSE-F2-BTR.pdf?dl=0 \$\endgroup\$
    – RobD
    Jun 3, 2020 at 3:50

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