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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 ?

Parents

  • I personally have a real issue with the courtyard approach (IPC standards) built into the footprints.  Every CM fab/assembly has different capability for density/spacing and with improvement in the pick/place equipment the spacing requirements will change.  If I put the clearances into the footprint it may cause excessive spacing when I need a high density design. Also as the pick/place equipment improves I'll need to go back and redo all the courtyards....  I've always thought these was a dumb approach by the IPC committee.

    The DFA Constraints spread sheet  built into the allegro tool on the other hand is a better approach.  I create place bound and the dfa bound geometries the same size as the physical body of the component.  The DFA constraint then shows errors for components too close.  I wish the courtyards would go the way of the dodo bird......

    My 2 Cents ......

Reply

  • I personally have a real issue with the courtyard approach (IPC standards) built into the footprints.  Every CM fab/assembly has different capability for density/spacing and with improvement in the pick/place equipment the spacing requirements will change.  If I put the clearances into the footprint it may cause excessive spacing when I need a high density design. Also as the pick/place equipment improves I'll need to go back and redo all the courtyards....  I've always thought these was a dumb approach by the IPC committee.

    The DFA Constraints spread sheet  built into the allegro tool on the other hand is a better approach.  I create place bound and the dfa bound geometries the same size as the physical body of the component.  The DFA constraint then shows errors for components too close.  I wish the courtyards would go the way of the dodo bird......

    My 2 Cents ......

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