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Calculation of differential pair impedance

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  • Calculation of differential pair impedance

    Hi guys
    I am using the Saturn PCB toolkit for calculating differential pair impedance and there is a 6 to 10 ohm difference between Saturn and allegro calculations for the same stack-up and trace width and spacing. can anybody help me with this problem? Which one should I trust?
    Also, which IPC standard does Allegro use for calculations? IPC-2152?

  • #2
    Only trust numbers from your PCB manufacturer. Everything else is just approximate.

    PS: I have explained this many times. Only PCB manufacturer can give you exact numbers, because manufacturing controlled impedance tracks is not only about putting theoretical numbers into a calculator - these numbers will change during PCB manufacturing process e.g. final dielectric thickness may be different.


    • #3
      Thank you ❤️ I have learned from you a lot. Do you know what IPC standard Allegro uses for impedance calculations?


      • #4
        Thank you for watching the videos. No, I don't know how Cadence calculates the impedance.