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Package to Package spacing

Lennie

My footprint's are created so the part outline is created on the PLACE_BOUND layer. We create this so the correct outline is used for  IDF file generation.

This layer is also used by the package to package DRC. I have not found a way to change the preset value from "0" package to package clearance. Since this places the footprints next to each other  then we cannot build the

board. Is there any way around that ?

  • I agree and I am moving to having 3D Models instead using the height and place_bound layer but have not got to that point yet. Thanks for the comment.

    I also agree the courtyard is not the best method to space parts and the DFA function is much more accurate and has more control.

    Since I use PCBLIBRARIES to create most of my footprints I decided to move the courtyard to layer DISPLAY_TOP from the DFA_BOUND_TOP . This way if there is nothing on the DFA_BOUND_TOP layer in thefootprints the Cadence DFA software uses the PLACE_BOUND_LAYER for DFA checks.

    There is also a program that Allegro provides that adds the DFA_BOUND_LAYER but that does not work as it creates the DFA_BOUND_LAYER with the outline that extends to either the package outline or the edge of pads.

    I believe this is a good solution. Anyone disagree ?

  • I also use PCB Libraries for some footprint creation. In the "Terminal > Density" level tab of PCBLE, you can set "Courtyard to ?" to 0 and it makes using DFA simple in PCB Editor. It will generate identical shapes for DFA_BOUND and PLACE_BOUND.

  • Thanks but tried that and unfortunately the outlines are not the same. The courtyard outline includes the pads.

  • in reply to Lennie

    Tom Hausherr is the owner of PCBLibraries AND the main influence of the PC consortium in SoCal. No wonder there are so many problems. Just sayin.

  • in reply to Lennie

    I agree, there is no working distance DRC between Placement boundary shapes in Orcad Pro or Allegro.   About the only thing you can do to it is disable it.    

    I will travel to the ends of the earth to avoid having libraries with different courtyard dimensions for about 600+ footprints.  Yuck. 

    So, I have Allegro PA-3100 for DFA rules. 

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