2
\$\begingroup\$

I am using vias to filter the input power. The following to pictures show two ways of placing vias. I think both of them are inappropriate since the vias are not "fully" connected with ground through all four "feet".

Is my guess correct? Could I have some comments on placing the vias?

via1 via2

\$\endgroup\$
5
  • 5
    \$\begingroup\$ I wouldn't let that second one anywhere near my boards... \$\endgroup\$ Jul 14, 2014 at 7:42
  • 2
    \$\begingroup\$ Why do you need thermal relief on a via? \$\endgroup\$ Jul 14, 2014 at 8:38
  • 1
    \$\begingroup\$ @VladimirCravero - You generally don't, but if you have extremely short traces between a via and a small SMT part, the solder on one end can reflow before the other, and the part will "tombstone". \$\endgroup\$ Jul 14, 2014 at 9:27
  • \$\begingroup\$ Trying to use vias to filter input power makes absolutely no sense. \$\endgroup\$ Apr 15, 2015 at 15:59
  • \$\begingroup\$ @OlinLathrop I was using vias to connect gnd with caps. Is that what you mean? \$\endgroup\$ Apr 17, 2015 at 3:23

2 Answers 2

1
\$\begingroup\$

First off, the second one looks absolutely horrid. Don't do that. Secondly, you should always envelop the actual drill with the trace, whether you need to make the trace large enough to envelop the thermals of the copper via is more a result as to how much current your trace will be carrying.

\$\endgroup\$
1
  • \$\begingroup\$ For the second point, why is that? The outer plate of a via encloses the drill already. \$\endgroup\$ Jul 16, 2014 at 2:03
0
\$\begingroup\$

What sort of filtration are you hoping the vias will deliver to your design? I've only heard of vias used for microwave filtration.

The second design is not good from a PCB manufacture standpoint because it has sharp inside corners which are likely to be etched out, making the shape of the trace different from what you are expecting.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.