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Constraint Region

PCB6453

In the Allegro Constraint Manager under Physical and Spacing, I can make a region for certain areas of the design.  Is there such a thing under Manufacturing?  My intent is to have different "Manufacturing" rules for certain parts of the PCB.  ie.  the whole board will follow Class 3 rules.  But on a smaller BGA area, I would like it to be Class 2 due to the pitch of the BGA.  I would create a region under Physical and Spacing but I'm wondering if we can do the same un "Manufacturing".  If this is not possible, any ideas on how to approach this?  Right now, the best thing I can do is run the check twice.  Once for Class 3 and ignore the errors within the BGA and run another one for Class 2.

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  • techiecs
    0

    Currently, DFM rules cannot be applied to constraint regions. DFM constraints can only be applied to layers/subclasses.
    However, you may explore some alternatives here:


    1 Apply constraints to layers or subclasses: Designers can apply manufacturing constraints to specific layers or subclasses, which can help achieve the desired results. For example, create a subclass for say nets of BGA and apply the Copper Feature constraint to that subclass.

    2 Apply DFA package-to-package rules to regions: While DFM rules cannot be applied to regions, DFA package-to-package rules can be applied to regions. This provides some option in applying constraints to specific areas of the design.

    Hence, by applying constraints to layers or subclasses and utilizing stackup-specific rules, you may explore these solutions to manage manufacturing constraints in your designs.

  • PCB6453
    0 in reply to techiecs

    Thank you.  I understand that DFM rules can't be applied to constraint regions.  I was just hoping that the DFM section also has another "constraint region" option specifically for the DFM section.

    Since I have 2 different set of rules (Class 2 and Class 3), I will just run it separately.  The problem of doing this is that it will do the whole entire board and will create so many errors.  Is there a way just to run a DRC check on a specific area of the PCB (like a BGA)?  In Mentor Graphics PADs, I can zoom in in a certain area and it will just run a DRC check on what is being shown on the screen.  It is just not the area, but also just the layers turned on.

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  • PCB6453
    0 in reply to techiecs

    Thank you.  I understand that DFM rules can't be applied to constraint regions.  I was just hoping that the DFM section also has another "constraint region" option specifically for the DFM section.

    Since I have 2 different set of rules (Class 2 and Class 3), I will just run it separately.  The problem of doing this is that it will do the whole entire board and will create so many errors.  Is there a way just to run a DRC check on a specific area of the PCB (like a BGA)?  In Mentor Graphics PADs, I can zoom in in a certain area and it will just run a DRC check on what is being shown on the screen.  It is just not the area, but also just the layers turned on.

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