Using Differential Pairs in Allegro PCB Editor
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Max Uncoupled Length
The maximum length for which the two nets of differential pair can run uncoupled is
constrained by the MAX_UNCOUPLED_LENGTH constraint. This constraint is available
in the Differential pair worksheet. If the two nets of the differential pair do not follow the
gap constraints for a certain length, which is more than the MAX_UNCOUPLED_LENGTH
constraint, the uncoupled length DRC is shown as D-U, and the uncoupled segments
are highlighted as displayed in the following image:
Note: At the group level, the max uncoupled length check can be based on the
individual from-to in the group or on the total from-to in the group (XNets). See Handling
Extended Nets for further details. However, at the class level, uncoupled length rule
applies to the individual net only.
