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  3. effective length variation after Monte Carlo trial

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effective length variation after Monte Carlo trial

inessadm
inessadm over 13 years ago

Hi, when I run a Monte Carlo analysis in Cadence Spectre-v 6.1.3 (process only), I'm looking for the variation effect
on each nominal length (L effective) of the circuit's transistors.  I find only the varied process data corresponding to
a particular run but nothing about width or length chosen for a trial !
Is there any way to do this please ?
Another question : what the meaning of process data as wd108, wd015, and so on ?
Thank you.

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  • Andrew Beckett
    Andrew Beckett over 13 years ago

    Quek - you beat me to it!

    In addition, it would only vary the length if the length of the devices was influenced by a parameter which had a statistical variation associated with it in a statistics block (see "spectre -h montecarlo") - and I've not seen that done very commonly in PDKs. Usually it's model parameters that are varied - although it could potentially be done with some of the model parameters that affect deltaW and deltaL - if so you'd be able to annotate the weff/leff parameters (from the same right mouse button menu that Quek pointed to) for a specific point - and then you'd be able to see on the schematic what the effective length for a specific device was. However, this assumes that the effective length was actually altered by the models. Note you'd probably also have to use the Edit->Component Display form to alter what is annotated on the schematic.

    BTW, stating what PDK you're using might mean that somebody familiar with that specific PDK might be able to give some more detailed advice - but the documentation for the PDK is a good place to start.

    Regards,

    Andrew.

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  • Andrew Beckett
    Andrew Beckett over 13 years ago

    Quek - you beat me to it!

    In addition, it would only vary the length if the length of the devices was influenced by a parameter which had a statistical variation associated with it in a statistics block (see "spectre -h montecarlo") - and I've not seen that done very commonly in PDKs. Usually it's model parameters that are varied - although it could potentially be done with some of the model parameters that affect deltaW and deltaL - if so you'd be able to annotate the weff/leff parameters (from the same right mouse button menu that Quek pointed to) for a specific point - and then you'd be able to see on the schematic what the effective length for a specific device was. However, this assumes that the effective length was actually altered by the models. Note you'd probably also have to use the Edit->Component Display form to alter what is annotated on the schematic.

    BTW, stating what PDK you're using might mean that somebody familiar with that specific PDK might be able to give some more detailed advice - but the documentation for the PDK is a good place to start.

    Regards,

    Andrew.

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