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Question of Monte Carlo simulation of Virtuoso 6.1.5

bhl3302

Hi All, I am trying to use monte carlo simulation for a bandgap voltage reference. When I followed the procedure in this forrum and other tutorial, and click "run" for "monte carlo sampling", it looks like nothing was executed. I post my setup and hope anybody can advise about it.

1. I have a cellview named "monte_carlo". In ADE L, the simulation output is "\net55" and it runs well over temperature -50C to 125C (DC simulation in sweeping the temperature). I selected and set "tt" to allmodels.scs, and select "design.scs". After running sussceesully, I saved this state as "temp".

2. I open ADE XL->"create new view"->"open in 'new window'"

3. Create test and load the state "temp".

Now the setup looks like this [Since I cannot insert an imagine from my computer here, I created a same thread in another place. The setup file picture is shown in http://www.edaboard.com/thread281229.html#post1203445. Please kindly go to this post to see the picture, sorry for the inconvenience]

 

When I click "run", it never showed any progress. For example, I set number of points to 100, then it always show 0/100. 

 

1.Could anybody advise how can I make simulation run? My target is to achieve some statistic distribution of output reference voltage.

2.Do I need to load more scs file here? like process.scs?

 

Thank you very much! 

  • Hi Andrew, I followed your advise but still got some proble. Here,in 27 Deg C, I want to run value(VT("/net055" 1)). And I set transient simulation time from 0s to 10s.

    When I finished running, it shows “finished with errors”. However, in CDS.LOG, it only shows 7 warnings. But I did get nothing here. Is there anyting wrong?

  • First run with single run sweeps and corners and make sure your expression works.

    You may need also to do a Right Mouse button click over the little terminal icon in the Run assistant to look at the log file to see if there are any errors. Which subversion are you using? (Help->About in the CIW).

    Regards,

    Andrew,

  • Hi Andrew, I did the single run and got the error again. However, I did not find the one you mentioned regarding run assistant. Could you tell me where is it.
    And the subversion is IC 6.1.5.500.16.2.
     

  • In your post /forums/p/25155/1322416.aspx#1322416 , in the bottom left corner there is a "Run Summary" assistant. Just below the checkbox that says "Nominal Corner" there is a little icon that appears for each parallel run - if you do right mouse button over this, you'll get a log file.

    Andrew.

  • Hi Andrew, thank you! Now I used DC simulation and save operating point, then there is no error in monte carlo simulation. However, the historgram still cannot be ploted. Could you help me in these two questions:

    (1) If I want to use DC operating point of net055 as the output, how can I write the expression? Is OP("/net055") OK?

    (2) Is there any .scs file I must include to run process and mismatch?

     Thank you! 

  • VDC("/net055") would be how to get the DC voltage (from the DC Op analysis) of the node in question.

    You need to ensure that you've included the model file containing the statistics block - details will be specific to the PDK you're using, so you should consult the PDK/model documentation for you technology.

    Regards,

    Andrew.

  • Hi ,

    bhl3302 witten ::  " the previous issue for monte carlo is caused by the IC6.1.5 itself. Now we have fixed it and make it run "

    Can you please tell me how did you fix the problem, In which Single Run,Sweeps and Corners were showing : running? I am facing same issues. Virtuoso IC 6.1.5.

    I am able to do all the settings but when I am hitting green button. It is just showing my 0/1 simulation running. After some time it is getting timed out message. 

     

  • Hi, I have exactly the same problem with IC6.1.5, could you please tell me how you solved the problem? Thanks

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