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Suppessing Line to Line DRC in DIFF PAIRS (Allegro 15.5)

Ragesh
Hi All,

Can anybody suggest me how to suppress Line to Line error between the diffpairs if the primary gap is more than line to to line spacing in spacing rule set.

Because the etch editing becomes difficult with more DRC's and some times even Allegro stops responding.

Seems to be like Environment variable " drc_diff_pair_overide = 0 " Under Drc in User preference Editor can suppress this DRC.

If any you have tried please suggest your thoughts?

Thanks in advance,
RMB
  • edhickey

    Most likely your "Min Line Spacing" constraint is not set. This constraint is part of the suite of Diff Pair rules that ensure the gap does not fall below primary or neck value less the Coupling Parameter "(-) tolerance". For example, if primary gap = 6 and negative tolerance = .2, set the Min Line Spacing to 5.8.

  • mcatramb91

    Hello,

    The Environment variable "drc_diff_pair_overide" is no longer valid in version 15.x and above but it is only left behind for uprev purposes only.  As "edhickey" indicated you will need to set your Min Line Spacing for the diff pair such that it is the worse case condition (Min Diff Pair Gap - Tolerance).  This will suppress the DRCs within the diff pair but still observer the Net Spacing Rule set from Diff Pair to Diff Pair.

    Hope this helps,
    Mike Catrambone

     

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