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Regarding monte carlo simulations

ag2888

Hi,

I am trying to run monte carlo simulations for my design and see the following trends in it.

The results vary if i add in a circuit which is not connected to the circuit for which the result is being considered.

The results vary even if i add in dummy devices, resistors etc.

If i manually choose the added devices to be ignored, only then the result remains the same.

Is this expected for the monte carlo sims?  

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  • ag2888

    Yes i meant the results are different when the additional devices are added in.

    But isn't this incorrect as this would mean we would have different results at every hierarchy. Then which result should we be considering? Also then at the top level even unrelated blocks will affect the results for every block?

    As an example, i saw the below results for the tests that i ran on 2 unrelated res divider circuits-

    Res div A and res div B have no connection to each other at all except they share the same ground.

    Initial MC run results (1 sigma) were : A output=1.39mV & B output=532uV

    But when I add 20 pieces of dummy resistors on res div B,1 sigma results were: A output=1.29mV & B output=2.74mV 


    Also wanted to clarify one thing, what exactly do you mean by - the results are still within the distribution of the parameters?

    Does it mean that results are still valid results as the random values for device parameters are chosen from the defined distribution data for the same? 

Reply
  • ag2888

    Yes i meant the results are different when the additional devices are added in.

    But isn't this incorrect as this would mean we would have different results at every hierarchy. Then which result should we be considering? Also then at the top level even unrelated blocks will affect the results for every block?

    As an example, i saw the below results for the tests that i ran on 2 unrelated res divider circuits-

    Res div A and res div B have no connection to each other at all except they share the same ground.

    Initial MC run results (1 sigma) were : A output=1.39mV & B output=532uV

    But when I add 20 pieces of dummy resistors on res div B,1 sigma results were: A output=1.29mV & B output=2.74mV 


    Also wanted to clarify one thing, what exactly do you mean by - the results are still within the distribution of the parameters?

    Does it mean that results are still valid results as the random values for device parameters are chosen from the defined distribution data for the same? 

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