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issue with dcmatch simulation

sarfraz

Hi,

I am performing dcmatch simulation for the first time. I am using TSMC 0.18u technology.

Now after simulation I get voltage 3-sigma variation  for voltage = +/-0V (i am simulating a bgr)

I am not sure if I am including the correct model files. I am using nch_mac models and added the inline subckt definition.

Can any body tell me typically which sections we include for such simulation? Is there some other files which I need to add.

  • dcmatch does not use the statistics block in the models; instead it requires special parameters in the device models. For example, in "spectre -h bsim4" there is this section:

    DC-mismatch dependent parameters:
    960     mvtwl=0.0 V*m     Threshold mismatch area dependence.
    961     mvtwl2=0.0 V*m^1.5
                              Threshold mismatch area square dependence.
    962     mvt0=0.0 V        Threshold mismatch intercept.
    963     mbewl=0.0 m       Beta mismatch area dependence.
    964     mbe0=0.0          Beta mismatch intercept.
    965     mismatchmod=0     Select Mismatch mode.
    966     mismatchdist=0 m  Mismatch Distance.

    So those are the relevant parameters. You may need to ask the foundry for models including these parameters if they are not present.

    Regards,

    Andrew.

     

  • Hi,

    does dcmatch still use special parameters in the device models or it now use statistical block in the models? 

    Thank you for your help

     

  • Since MMSIM12.1.1 (the MMSIM12.1 Update release) dcmatch now supports two methods - one is the original (standard) which requires parameters in the model, and the second is "statistics" which uses the monte carlo statistics parameters.

    There were some initial issues so you should use at least MMSIM12.1 ISR16 or MMSIM13.1 ISR2.

    In recent IC versions the UI has been updated (see attached picture) to allow you to choose this. With older versions, go to the options form for the dcmatch analysis and in the additional parameters field, type "method=statistics".

    Regards,

    Andrew.

     

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