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ADEXL measurement for temp drift of an output variable

vamshiky

Hi,

I have to measure a frequency of a circuit at  room temp, cold and hot.

and want the percentage change in frequency from room temp to cold and hot  in every process corner.(and any other global variable)

ex: ratio of  Freq_125C/Freq_25degC  is what I want in all corner  sims.

Please suggest any solution to do this within adexl, as presently I am copying data manually into an excel sheet and doing it.

Thanks,

Vamshi

  • Hi Vamshi,

    If you use IC616 ISR12 or later (IC6.1.6.500.12) then you can use a new feature of the calcVal() function which allows specifying a specific corner. To use this, I'm assuming  you have an output called "Freq" - then add a new output called (say) FreqRatio, with the expression:

    calcVal("Freq")/calcVal("Freq" ?cornerName "Nominal")

    If the cornerName is "Nominal" (with a capital N) it's referring to the "Nominal" run - i.e. using the models etc from the test. Alternatively, if you have a specific corner name to retrieve the results from (e.g.  "C0_0") you can use that too.

    Regards,

    Andrew.

  • Hi Andrew,

    Thanks for the reply , I have ISR11 only here,  and so your suggested expr seems to fail.

    probably the question now boils to how to grep an output expression value of a particular PVT corner+global/design variable (among some 100 such) in a new ADEXL output expression ?

    so that I can have ratio later.

    Thanks,

    Vamshi

  • Vamshi,

    There's no real API to do this until ISR12, so that would be your best solution. There's no "grep the particular PVT corner" option that would make any sense - for a start, one of the things that calcVal does is to ensure the order dependency is observed. Given that the simulations could potentially start and complete in any order, it's important for ADE XL to be able to keep track of the fact that it can't calculate any expression with a dependency on another result until that other result is available.

    So your best bet is to use a later ISR rather than attempt to come up with complicated solutions that would most likely not work reliably.

    Regards,

    Andrew.

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