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PADS ROUTER problems trying to route diff pairs

Question asked by bachille on Nov 13, 2012
Latest reply on Nov 27, 2012 by bachille

It has been a while since I have used PADS and i am having a tough time figuring out the finer points of the Router. I have Interactively routed a handful of Differential Pairs with rules migrated from Layout. Routing the pairs works pretty well, but I am seeing some strange behavior when I try to edit the pairs.

1. When I stretch one of the pairs, there is a point where the defined spacing rule is no longer maintained. ie. one route will pop far away from its partner.

2. Interactive router puts in several unneccesary jogs in the pairs that are quite frustrating to edit.

3. Some of my diffpairs need to be matched length and the only way I could do this was to route the longest pair, protect the pair, route the next pair, tune it, protect and so on. Any better way?

4. Sometimes for no obvious reason only one of the diff pairs wanted to be routed at a time, in other words the pair would not route simultaneously. Checked all my rules, seemed OK. And then poof, suddenly it would start working again. Don't know what I did, if anything.


As with all tools it takes some finesse to make them work properly, I am just not used to a tool that seems to be on Auto-pilot half the time; doing something in the background without giving the user much explanation of why. Any suggestions from seasoned users would be greatly appreciated. There are tons of "how to" pdfs from Mentor Graphics, the few that I have looked at only touch the surface on how to do what I am trying to do. Does anyone know of a good document that covers Routing diff pairs  in PADS and goes deeper than just the basics?



Brad Achille