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 Package to package clearance 

Last post Fri, Aug 26 2011 1:46 AM by RiskCord. 3 replies.
Started by RiskCord 25 Aug 2011 06:23 AM. Topic has 3 replies and 2815 views
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  • Thu, Aug 25 2011 6:23 AM

    • RiskCord
    • Not Ranked
    • Joined on Tue, Mar 22 2011
    • Tullamore, Ossally
    • Posts 6
    • Points 90
    Package to package clearance Reply

    Hello everybody!

    Another newbie here! My issue goes as follows:

    I am building my component symbols libraries for my project, and am working with the design guidelines from the PCB manufacturer. There, they require what they call a "Placement Keepout Area to Neighboring Component Placement Keepout Area", that is a placement keepout or courtyard from other component placement keepouts, to ensure certain clearance between components.

    The question goes, which is the best way to define this clearance when creating the part symbols? The easiest way I guess would be to set the package boundary so that it cover the real physical boundary of the package plus the required clearance. The drawback of this, is that the 2-1/2 view will now display the package + clearance. Is there any other bound or keepout that would do the trick?

     Thank you very much!

    • Post Points: 35
  • Thu, Aug 25 2011 1:23 PM

    • KEN13
    • Top 75 Contributor
    • Joined on Wed, Aug 6 2008
    • Pleasant Valley, CT
    • Posts 113
    • Points 1,800
    Re: Package to package clearance Reply

    Risk,

       If you want specific spacing for different components, not sure how to set that up.  If you are refering to a global spacing between parts on the PCB...Create the footprint with the boundry being the maximum size of the part.  Then in PCB Editor open the contraint manager, select the Spacing tab on the left and entered the desired values for the various spacings.

    Have a good day, Ken Capture 16.5 S022, Layout 16.2.0p001, PCB Editor 16.5 S025
    • Post Points: 5
  • Thu, Aug 25 2011 7:27 PM

    • redwire
    • Top 10 Contributor
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    • Allen, TX
    • Posts 875
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    Re: Package to package clearance Reply

    I'm confused.  Isn't this what PLACE_BOUND_TOP and PLACE_BOUND_BOTTOM used for?

    • Post Points: 20
  • Fri, Aug 26 2011 1:46 AM

    • RiskCord
    • Not Ranked
    • Joined on Tue, Mar 22 2011
    • Tullamore, Ossally
    • Posts 6
    • Points 90
    Re: Package to package clearance Reply

    Thank you guys for your answer.

    redwire: Yes, I guess that's what Place_bound_top and bottom are used for. The only reason I wanted to find a different was not to "alter" the 3d view, i.e. that in the 3d view I would get only the package surface and not package + clearance. However, I checked with the PCB manufacturer desing rules and these clearances are in general not that big (15 mils average) so it doesn't make a huge impact on the 3D view in my particular design.

    I was also suggested to stack two Place_bound_top boundaries (they can be stacked to define different 3D shapes (other than a rectangle). So the idea would be to put one place boundary including the required inter-package clearance with a height of say 1 mil and then another place boundary with the real physical dimensions .

    Another possiblity (I guess) would be to use the DFA feature... but I haven't got that far yet!

    • Post Points: 5
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Started by RiskCord at 25 Aug 2011 06:23 AM. Topic has 3 replies.