7 Replies Latest reply on Mar 18, 2019 2:09 AM by weston_beal

    Adding Parasitic Resistances




      I have been using the PI tool for a little while, and it would be very helpful if there were an easy way to assign parasitic resistances to the inductors on my board.  Is there anyway to do this in HyperLynx?

        • 1. Re: Adding Parasitic Resistances

          HI Matthew. I've moved your question to the HyperLynx SI/PI community where it should get a quicker response.

          • 2. Re: Adding Parasitic Resistances



            We can help you more if you can be more specific about what task you are trying to run. The PI side of HyperLynx has a few different types of analysis, and the model details can be different for the different analyses. I will assume that you are doing DC drop or Decoupling analysis and that you are referring to series inductors connected between power supply nets.


            In my example, I have L9 that connects different power nets of the same voltage (1.35V). Select the menu Models > Assign Power Integrity Models... and the PI model dialog opens. Select the tab, Supply-Net Inductors and then select the reference designator of the inductor that you want to edit.



            Here, you can edit both the inductance and resistance values of the chosen inductor.


            Also, there is some useful information in this knowledge base article about setting up the Advanced Decoupling Wizard.



            Let us know if you are working on a different task that needs a different modeling method.




            • 3. Re: Adding Parasitic Resistances

              Hi Weston,


              Thank you very much! That is exactly the feature I was looking for.




              • 4. Re: Adding Parasitic Resistances

                Is there a possiblity to add this information directly at the schematic entry or load it from a file depending on the part number?

                We have a lot of inductors and I do not want to add them by hand.


                Regards Stefan

                • 5. Re: Adding Parasitic Resistances



                  You can assign models by part number in the QPL file. Use the menu Models > Assign Models/Values by Part Number. You can easily assign inductor values this way. You can also assign series IBIS models that include series resistance. It is easy to see model or value assignments set by the QPL file. The reference designator will have a green check mark with a little letter Q as in the image below.



                  I created this assignment to an IBIS file that includes a series resistance with the inductance. The resistance value does not show up in this dialog, but it is probably present in simulations. I did not check the simulation results.



                  • 6. Re: Adding Parasitic Resistances

                    Could you give an example of such an inductor ibis model?




                    Nevertheless, I am afraid the dc drop will assume zero ohm, but I will test.




                    Regards Stefan

                    • 7. Re: Adding Parasitic Resistances

                      The attached file is an IBIS inductor with series resistance.