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Differential Pair Setup of Class to Class

Sagetech

Trying to configure differential pair spacing from pair to pair and other traces.

I've been following the Parallel Systems Differential Pair tutorial but I'm not getting the results I need. 

I have my diff pair trace width and spacing set up in the physical cset.

I set up a spacing cset and net class to get my pair to pair spacing constrained. When I do this, the pairs do seem to adhere to the pair to pair spacing constraint but I get a DRC on the differential pair line to line spacing set in the physical constraint. If I remove the spacing cset, the pair spacing DRC goes away but the pair to pair spacing is no longer constrained and I can route one pair too close to the next pair.

Been through the instructions a dozen times with the same result. Instructions were published in 2020, maybe things have changed since then?

Thoughts / suggestions?

Tom

  • avant
    0 in reply to Sagetech

    Try assigning each pair (or net group) a unique net class name.

    Then go to the CSet assignment matrix and assign a spacing rule at the intersections of the row and colums of the net classes you want to control.

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