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Spectre Error using S-parameter with Multiple Reference Impedances

gwong

Error:Mismatch found between number of data and number of ports

I'm getting the above error when using s-parameter file that has multiple reference impedances: 

#       Hz      S       RI      R       1 1 50 50 1 1 50 50

If I change the line to (single reference impedance for all ports) the following, it works

#       Hz      S       RI      R       50

What's the proper way of defining multiple impedances so Spectre will run.

 Regards,

Gary

Parents
  •  Tawna-

    Touchstone files with multiple normalizing impedances are commonly utilized in simultaneous switching noise simulations where the s-parameters in the Touchstone file characterize both signal nets (normalized to 50 ohms) and  PDNs (power distribution nets) which are typically normalized to 0.1 ohms.

     

    Since PDN nets are low impedance structures, choosing a normalization impedance near the net impedance prevents the magnitude of the s-parameters from assuming very small numbers which can provide better numerical robustness,

     -Ray

     

    Raymond Anderson

    Senior Signal Integrity Staff Engineer

    Programmable Platforms Development

    Silicon Technology Group

    Signal Integrity and Package Development Department

    Xilinx Inc.

    San Jose, California  95124
Reply
  •  Tawna-

    Touchstone files with multiple normalizing impedances are commonly utilized in simultaneous switching noise simulations where the s-parameters in the Touchstone file characterize both signal nets (normalized to 50 ohms) and  PDNs (power distribution nets) which are typically normalized to 0.1 ohms.

     

    Since PDN nets are low impedance structures, choosing a normalization impedance near the net impedance prevents the magnitude of the s-parameters from assuming very small numbers which can provide better numerical robustness,

     -Ray

     

    Raymond Anderson

    Senior Signal Integrity Staff Engineer

    Programmable Platforms Development

    Silicon Technology Group

    Signal Integrity and Package Development Department

    Xilinx Inc.

    San Jose, California  95124
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