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Automatically Updating Impedance Based Physical Csets After Stackup Changes.

Electro Node

Hi Community,

Is there a way in Cadence tools to automatically recreate or update impedance‑based physical constraint sets when stackup parameters (such as dielectric constant or layer thickness) change in the Cross‑Section Editor?

I’m looking for a solution that can recalculate line widths and spacing to meet impedance requirements for high‑speed interfaces across all layers, without manual rework.

Any recommended tools, flows, or best practices would be appreciated.

Thanks!

  • Electro Node
    0 in reply to excellon1

    Hi Excellon1,


    Thanks for taking the time to think about this. Yes, I am also not very proficient in this skill. We can try using a script as well, if you have any suggestions, please do share; it would be great to explore them.


    Additionally, I am also checking if there is anything new in 25.1 from the stackup itself to achieve the same.

    Kind regards

  • steve
    +1 in reply to Electro Node

    Hi 24.1 and 25.1 has a feature that allows you to do this from the stackup. Launch the cross section editor and click on the Primary tab, You will see a column Add Physical CSet. Once selected fill in the specfied values. A Cset is calculated based on the cross section and added here and in Constraint Manager. If you need to change it, adjust the cross section then right click the CSet name and choose edit then check the box for recalculate width from Target. This will update the widths for the CSet in the cross section and in Constraint Manager. 

  • Electro Node
    0 in reply to steve

    Hi Steve,


    Thank you so much for your response. This is exactly what I was looking for.
    This is really a great enhancement in the tool. I have just tried it, and it will save a lot of my time and effort.


    Your help in this matter is truly appreciated. Thank you so much.


    Regards,

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