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49,904 Views 5 Replies Last post: May 30, 2012 4:12 PM by ksamrick

ksamrick

6 posts since
May 29, 2012

Currently Being Moderated

May 29, 2012 2:02 PM

Creating a test point

Hi,

I've been using PADS for a week, and am having trouble creating a simple test point. I'm designing a simple board that consists of 50 Ohm traces terminated in different ways so that students can see the effects of improper termination. All I need is a hole in the solder mask, which I think I can do with a surface mount via, so that students can stick a probe in there and look at the signal. I know there has to be an easy way to do this and feel silly for asking, but after spending a few hours looking through forums and playing around with PADS Layout, I'm at wits end.

Thank you very much,

Kevin

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jmatthews

130 posts since
Jul 27, 2010

Currently Being Moderated

May 29, 2012 2:32 PM

in response to: ksamrick

Re: Creating a test point

Create a via and name it whatever you think is appropriate, 35TP for example (where 35 is 35 mils).

The pad stack for that TP via could be (bear with me, my personal terminology is different than the PADS standard):

Primary Side: 35 RD Pad

Inner layers: 0 RD Pad

Secondary Side: 0 RD Pad

Primary Soldermask: 41 RD Pad

Primary Solderpaste: No pad

Drill size: 0

I think PADS still makes you place a "regular" via first, you can then select and query the vias you want to change and switch them to 35TP. Set them as Test Points at the same time. I usually glue them also.

For a bottom-side TP, just use a TH (or SMT where appropriate, with a pad stack the reverse of the one I showed above) via. You can set the probe side pad to a different size than the other side if you wish/need to.

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cathy_terwedow

152 posts since
Jul 7, 2008

Currently Being Moderated

May 29, 2012 2:55 PM

in response to: jmatthews

Re: Creating a test point

Thanks John. I knew somebody would provide a quick answer to the technical aspects of Kevin's question!

And Kevin, I've got to tell you, your timing is perfect as far as asking about testpoints.

We are hosting a webinar next Tuesday, about how to analyze, verify, and provide PCB test point coverage and reporting before releasing your PCB for fabrication.

The webinar is June 5, at 2pm EDT. Registration and more info.

I hope you'll attend!

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ksamrick

6 posts since
May 29, 2012

Currently Being Moderated

May 30, 2012 10:55 AM

in response to: jmatthews

Re: Creating a test point

Hi jmatthews,

Thank you for your quick reply. I was able to create a new Via, I just can't figure out how to place them. When I did my initial design, I used the various rules and autorouter, and PADS placed all the Vias for me. How does one actually add additional Vias independently. Again, I've looked online, and for some reason I haven't been able to find anything.

Thank you again,

Kevin