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When setting temperature as a design/global variable, it is called an unknown parameter and a simulation error occurs

jackrc11

I'm trying to simulate a PTAT current source in a transient analysis (where the temperature coefficient on a ipwl does not do anything). However, after making temperature a variable in this current source's expression and setting it as a design variable in Maestro, I get a simulation error stating it is an unknown parameter:

Error found by spectre during hierarchy flattening.
ERROR (SFE-1997): "netlist" 1403: Cannot run the simulation because I0: parameter `wave': Unknown parameter `temperature' has been specified in expression `((500e-09)+(temperature-27)*(1.687759e-09))', correct the expression and rerun the simulation.

I am running sub-version  ICADVM20.1-64b.500.27.EHF11760.

  • ShawnLogan

    Dear jackrc11,

    jackrc11 said:
    However, after making temperature a variable in this current source's expression and setting it as a design variable in Maestro, I get a simulation error stating it is an unknown parameter:

    I believe you need to refer to the simulation temperature in your expression as VAR("temp") in lieu of your design variable "temperature". This is a frequent point of confusion so you are not alone! There is a recently published  On-line support Troubleshooting article that attempts to clarify the proper syntax to use when referring to the simulation temperature and the nominal temperature in expressions and models at URL:

    https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009xxe7EAA&pageName=ArticleContent

    Have you tried replacing your use of "temperature" in your expressions with VAR("temp")?

    Shawn

  • Andrew Beckett
    in reply to ShawnLogan

    Actually, if it's an expression on a spectre isource then it becomes a bsource and so you should use "temp" to refer to the in-simulation temperature. VAR("temp") is for output expressions in the ADE output pane (for example).

    Andrew

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