Vias on top of pads

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Vias on top of pads

    by kane » Tue Nov 06, 2012 9:06 am

I have a .DRU (design rules) files from Sunstone (sunstone-valueproto.dru) that has a required 7mil gap between vias and pads of the same signal. Does this mean that I cannot place vias directly on top of pads of the same net?

thanks.
kane
 
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Joined: Tue Nov 06, 2012 8:35 am

Re: Vias on top of pads

    by Sal Hernandez » Wed Nov 07, 2012 6:40 am

You can place vias directly on top of pads if the two are connected to the same net. When placing a via on top of an SMT pad you could experience solder wicking during assembly. The document linked below from our partner company Screaming Circuits provides more information on the topic.

Via_In_Pad_Guidelines
Regards,

Sal Hernandez
Software Support Engineer I
Sunstone Circuits
13626 S. Freeman Road
Mulino, OR 97042
Phone: 503-829-9108 x226
Fax: 503-829-5482
Sal Hernandez
 
Posts: 381
Joined: Wed Jul 06, 2011 12:00 am

Re: Vias on top of pads

    by danatdst » Mon Dec 30, 2013 11:54 am

The aforementioned document from Screaming Circuits, "Via_In_Pad_Guidelines", recommends the following best practice:

"Have your board fab house plug the via and then plate copper over it. They can plug with metal or a thermally and electrically conductive epoxy before the final plating steps."

What is the appropriate method to communicate to Sunstone which vias should be handled this way?

Thanks.
danatdst
 
Posts: 1
Joined: Mon Dec 30, 2013 11:31 am

Re: Vias on top of pads

    by Sal Hernandez » Thu Jan 02, 2014 6:43 am

A drill drawing note or fabrication drawing note should be fine. If a particular hole size or component's vias should be filled you can specify the size, reference designators, and general location in text on one of the layers mentioned to let our Custom Quote team know that you need filled vias. Filled vias are only available through our Custom Quote service.
Regards,

Sal Hernandez
Software Support Engineer I
Sunstone Circuits
13626 S. Freeman Road
Mulino, OR 97042
Phone: 503-829-9108 x226
Fax: 503-829-5482
Sal Hernandez
 
Posts: 381
Joined: Wed Jul 06, 2011 12:00 am




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