5 Replies Latest reply on Jun 8, 2011 4:58 AM by strangd

    Impedance calculation without reference to plane data?

    matheisl.florian

      Hello everybody,

       

      i have a question/problem with the right impedance of a Trace/DiffPair.

      Impedance_FieldSolver.jpg

      The Field Solver dialog shows a picture with the magnetic field to the neighbour layers of the highlighted trace segment.

       

       

      But on  the yellow Plane Layer 2 isn´t a valid plane data, the plane in this region is free from any copper:

      Impedance_Plane.jpg

      - cutout picture of the yellow plane layer

       

       

      So the FieldSolver and the whole impedance calculation isn´t right at all, I think?!

      Or is there an option to include a check to referenced plane datas?

       

      Thanks,

       

      Best wishes,

       

       

      Matheisl Florian

        • 1. Re: Impedance calculation without reference to plane data?
          yu.yanfeng

          Hi Matheisl,

          Hyperlynx suppose the reference plane layer is an ideal reference plane, no any of copper cutoffs be recongnized while calculating the trace's impedence. You may change the plane layer to signal type and assign another layer to the plane layer type.

           

          Yanfeng

          • 2. Re: Impedance calculation without reference to plane data?
            artsiom.shchatsko

            HyperLynx can't calculate it, you'd need a proper 3D field solver for that. But to get an approximate impedance you might temporarily set the top plane layer to "signal" (as suggested)

            • 3. Re: Impedance calculation without reference to plane data?
              Steve_McKinney

              Yanfeng is correct - right now the reference is assumed to be ideal.  The work around he proposed will work but it will chance the impedance on the whole trace, so just be aware of that.  Another option would be to export the diff pair into LineSim and then you can have some more freedoms to have some traces have a reference by making them co-planar (embedding them into the reference layer, so there is no reference) and other traces having the proper reference.  If you need help with this,  enter a service request and customer support should be able to get you going.

               

              One final comment, we plan on addressing the effect of non-ideal planess in a future release of HyperLynx for impedance calculations.  We have the technology today in our ICX product and will be bringing over into HyperLynx.  This will no address all the effects of a non-ideal plane (such as return path). For that, you need a 3D solver (such as our IE3D product) which is what Yanfeng was refering to. 

               

              -Steve

              • 4. Re: Impedance calculation without reference to plane data?
                matheisl.florian

                Thanks for your answers,

                 

                it was a test only to show what hyperlynx can do and what not.

                 

                 

                One final comment, we plan on addressing the effect of non-ideal planess in a future release of HyperLynx for impedance calculations.  We have the technology today in our ICX product and will be bringing over into HyperLynx.  This will no address all the effects of a non-ideal plane (such as return path). For that, you need a 3D solver (such as our IE3D product) which is what Yanfeng was refering to.

                This would be good for verfying highspeed designs

                 

                Florian

                • 5. Re: Impedance calculation without reference to plane data?
                  strangd

                  With IE3D on its way to do via impedance calculations for HyperLynx is IE3D also going to be allowed to do these dif pair calculations?  Or will we have to buy a stand-alone version?

                   

                  Dwain