FEDEVEL
Platform forum

joshua , 08-31-2024, 12:53 PM

I want to know how to change width and gap of diff pair by changing Rules however I use retrace selected or Gloss and unfortunately the shape of tracks change and I don't want to change the shape of tracks just gap and width. thanks

QDrives , 08-31-2024, 01:08 PM

If you change the width and/or gap of a differential pair, the traces need to move.
If you do not want Altium to change the 'path' of the traces too, there is only one option: do it manually.

joshua , 08-31-2024, 01:13 PM

factory change the stack up that needs change lots of diff pairs and altium change the path in unusual way unfortunately

QDrives , 08-31-2024, 04:32 PM

I would say that the gap is very big.

joshua , 08-31-2024, 04:52 PM

10 MIL that should be 6~8 mil based to change stack up

QDrives , 09-01-2024, 02:55 PM

Shouldn't the width then also be bigger?

Robert Feranec , 09-03-2024, 04:46 AM

if they change stackup, often they are able to fine tune already routed pairs by changing width and space while keeping the total width of diff pair the same. it is not ideal as the width of diff pair track should often be close to 50OHM but if the stackup change is not big, usually it is ok. If the stackup change is big .... then yes, it needs to be re-routed.