1 Reply Latest reply on Jul 23, 2012 5:02 AM by matthias.cosaert

    Nets of diff_piar puzzle

    gaoliuan

      These days , I found a strange phenomenon,this problem led me stop my work,so I would like to ask ,I paint diff_pair ,give a simple example

      ,each line through a capacitor ,a differential line through two capacitors.Assume the net in front of the capacitors are :IN_P,IN_N, the net behind

      the capacitors are seted to be OUT_P,OUT_N, In schematic they were seted to be diff_pair ,general we want the two diff_pairs should be

      independent,however,something happened,afer we set them to be th diff_pairs, OUT_P,OUT_IN will includ IN_P,IN_N, it means that IN_P

      will inside in OUT_P, IN_N will inside in OUT_N, the nets OUT_P and IN_P look like the same one,the nets OUT_P and IN_P look like the same one too,

      Then I use ANALOG seprate them from each other , and I want to see if I can set them independent, then strange things happened I can set the IN_P and IN_N into a differential pair,

      but cannot set OUT_P and OUT_N to be a differential pair.

      The tips is” the Electrical NET OUT_P OUT_N is a power net, and it cannot be used to creat the diff pair”. But surely they are not power net at all. What can I DO,Who can help me , thank you ~ ~ ~

        • 1. Re: Nets of diff_piar puzzle
          matthias.cosaert

          Power nets in the constraint editor are set in Setup -> Settings -> Power and Grounds.

          It automatically sets net to power if they are above a certain pincount (can be set in Setup -> Settings -> Electical nets at the front end CES) and I think also with ibis model pin types but never tried that.