Using Differential Pairs in Allegro PCB Editor
February 9, 2012 12 Product Version 16.5
Resizing a Differential Pair
If a differential pair is already routed with specified gap, is there a way to change the
Differential pair spacing?
Use the unsupported command to resize the differential pairs. This command is useful
when differential pair constraint changes are required after differential pair routing is
complete.
Gap changes are typically accomplished by maintaining the existing (imaginary) center- line
between coupled segments. When modifying any differential pairs, neighboring elements
are ignored, so DRCs are likely to appear after the command is run. Constraints are not
modified, and will need to be changed to match the Resize/Respace values applied.
Note: An important step is to run the Resize/Respace Diff Pairs command before (and not
after) changing the constraints. You should not run this command again on the same
differential pairs until after having updated the constraints to match the applied
Resize/Respace values. Else, the command will not recognize the modified differential
pair clines accurately.
Examples
