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Help making footprint?

Former Member

I am making my first footprint in Eagle.  I am basing it on this datasheet http://www.memoryprotectiondevices.com/datasheets/BH800S-datasheet.pdf and the problem I am having is with the pads.  The drill diagram at the top of the sheet shows a .042 drill but when I enter that into Drill on the Info screen for the pad and choose Auto for the diameter, it draws a pad that is much smaller than what it seems it should be from the diagram on the lower right. What, if anything am I doing wrong?  Also, what does 2PL mean on the drill hole callout?  

 

Next, I am confused about the three circles on the .750 diameter circle on the lower right diagram.  What are they and why is there no position or size information associated with them?  Finally, the center diagram shows a locking stake (again with the 2PL notation) but without any location or size  information. Any ideas on that?   I guess it might help if I had a device in hand to look at but at this moment I do not.

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  • 0

    Hi

     

    Do you need to make a footprint for this? I may be wrong and will check in more detail for you, however it looks like a standard coin cell holder, sparkfun have a very useful library of footprints/parts you can download here

     

    They have some coin cell holders in BATTERY section. There is a 20mm one there BATTERYPTH20...might it do? you will find the sparkfun library useful in any case...

     

    Im guessing as far as the PCB footprint is concerned, from the datasheet it looks like there are only 2 x 1mm holes 20.50mm apart that are needed for the part, one for positive, and the other negative.

     

    Regards

    David

  • 0 in reply to robotonics

    Yeah, I wish Sparkfun had a footprint for this particular coin cell holder but they don't.  This holder is for two cells and it is one of the few I coud find.  It is the one closest to one from SF, which I am modifying to make this one. 

     

    So, the question remains, how do you explain the difference between the diagram on the lower right in the datasheet and the rather small holes that are drawn using .042 for the drill size?   And the other questions are still unanswered as well.

  • 0 in reply to Former Member

    Thats the trouble...lol...never enough detail...And that datasheet is bad. If you have the part in front of you its a lot easier obviously.

     

    However, I am looking at the PCB LAYOUT part, and ignoring the rest.

     

    I can see holes drilled in 2 places 20.50mm apart and approx 1mm in dia...you will want pads round them as well obviously.

     

    Are there any more than 2 connections for this part?

     

    The holes at lower right are probably not holes but just the dimension of the top of the pin, a bit like a flat head nail...the hole you see on PCB layout is the actual dimension of the pin that will go through the PCB..the pin end.

     

    The other 3 holes seem to be in the plastic only and carry the locking pins that hold the whole assembly in place.

     

    Am I making sense?

  • 0 in reply to Former Member

    Looks like a standard battery holder for a CR2032 3.0V Lithium Coin Cell.

    All the the ones I have seen of that style are pretty much the same.

    2PL means "2 Places", the holes in the lower right diagram are exagerated, the 3 circles in the lower right diagram are molded feet (part of the holder) that keeps the holder up slightly off the surface of the board for an air gap. I'm not positive what the locking stake is except maybe the portion of the contact pin that is slightly wider than at the point of entry Never really seen it used for anything specific except to keep the pins from going too far into the pad..

     

    If it's for 2 coin cells then it would be 2 ea. CR2016's stacked one on top of the other to make 6V instead of 3V.

     

    lol....correcting myself 2 ea. CR2032's stacked, it's too deep for 2 CR2016's.

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  • 0 in reply to Former Member

    Looks like a standard battery holder for a CR2032 3.0V Lithium Coin Cell.

    All the the ones I have seen of that style are pretty much the same.

    2PL means "2 Places", the holes in the lower right diagram are exagerated, the 3 circles in the lower right diagram are molded feet (part of the holder) that keeps the holder up slightly off the surface of the board for an air gap. I'm not positive what the locking stake is except maybe the portion of the contact pin that is slightly wider than at the point of entry Never really seen it used for anything specific except to keep the pins from going too far into the pad..

     

    If it's for 2 coin cells then it would be 2 ea. CR2016's stacked one on top of the other to make 6V instead of 3V.

     

    lol....correcting myself 2 ea. CR2032's stacked, it's too deep for 2 CR2016's.

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