Adafruit Eagle Part Generating Errors (CR2032-THRU)
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Adafruit Eagle Part Generating Errors (CR2032-THRU)

by sciguy77 on Fri Feb 01, 2013 11:26 pm

Hi guys,

So I'm mounting a coin cell on the back of my pcb using the CR2032 through hole part from the Adafruit Eagle library. When I send it off to my fab they email me, "Soldermask relief is exposing trace on bottom layer." I had one made anyway, see the attached image of the part. Is the exposure of traces intentional? Does this mean I'm not supposed to have any traces routed around that area? My pcb board is just barely bigger than the battery holder so this would not be possible. Is the solder relief necessary? If not, how do I get rid of it?
I'd love to hear you guys' thoughts.

Thanks!
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by thefatmoop on Sat Feb 02, 2013 2:06 pm

Can you believe it's 2013 and we still can't make a phone camera that can focus? You don't want any solder mask on that square, but you do on the traces around it.

if I understand correctly
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by sciguy77 on Sat Feb 02, 2013 6:18 pm

Sorry about that, used my iPhone camera and that was the best of ~10 shots. It doesn't like to take photos of tiny things.

Should I draw solder mask over the traces by hand in the .brd file?
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by Zener on Sat Feb 02, 2013 6:24 pm

It depends what you are putting there. Are you putting a battery holder? If so it is probably OK as is. You just don't want anything shorting to those traces.
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by Zener on Sat Feb 02, 2013 6:29 pm

As far as picture quality, nothing approaches my old Blackberry! I hated the web (un)usability but the camera was superior. I have an iPhone now and it never ceases to provide dull blurry photos. I keep the Blackberry around in case I need to shoot any close ups like that, or any photos that need to look good.
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by sciguy77 on Sat Feb 02, 2013 6:33 pm

I'm using one of these guys: http://www.digikey.com/product-detail/e ... ND/2194764

As you can see, the battery will likely be touching the entire diameter of the relief circle, so shorting seems like a definite risk...
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by Zener on Sat Feb 02, 2013 7:03 pm

That is an interesting holder. So it appears one side of the battery is supposed to directly touch the board. The bigger problem I see is the 6 pads in there which I assume are for components. There are different ways to fix the problem. I am not sure what I would do.
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by sciguy77 on Sat Feb 02, 2013 7:08 pm

I've made some changes to the board, and I'm now using surface mount components on the top layer. Looks like I can just draw some solder mask on top of the traces and that should solve everything...
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by Zener on Sat Feb 02, 2013 8:30 pm

My concern is the mask will lift the battery just enough to keep it from touching the square pad. You might want to build up the height of the square pad by adding a little solder to it
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Re: Adafruit Eagle Part Generating Errors (CR2032-THRU)

by trevynw on Sun Nov 03, 2013 1:29 pm

I used the surface mount version of this part on a board I'm designing and noticed that circle in the solder mask layer while inspecting my Gerbers (always inspect your Gerbers before sending them to the board house!). It's a circle in the tStop layer in the part, which means that soldermask won't cover there. I don't see any reason for it - as you found, it will only cause traces routed under the battery to be exposed. It might make sense for it to be on the tKeepout layer so that the DRC will catch components placed under the battery holder. I pulled the part into my library and changed the circle to tKeepout.

As a side note, I've used holders like this before, and (soldermask or not?) you will need to put a little dome of solder on the center pad to ensure reliable contact.
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