Monte Carlo - circuit exlusion

[skoda]

Hi to all IC designers and engeneers !

Does anybody try to do monte carlo simulation to only a part of cicuit? For example in simple ota, how to make Monte Carlo only on diff.pair?

 

[skoda]

I have some idea,

what if I make a new library "XZ_MC" and into this library a copy standart device nmos/pmos/res etc...
If I change In ADEL Model Library setup from stat to nn monte carlo should take them into simulation, is it right?
Anyway I don't know how I can attach new library to this copyed devices

 

[haykding]

I think you can create model of MOS transistor which will have different name and will have agauss statement in it.
And you need to change model name only for diff pair. Other transistors need to be leaved as is (w/o monte carlo library ).

 

[beetwee]

It depends on the tools and PDK. Some PDK's have different transistors in the library for monte carlo simulations. In other PDK's it's an option in the transistor properties.
In AdeXL you can also select which devices should be included in the monte carlo analysis.

 

[haykding]

If the ADEXL has capability you mentioned why are you not using it ?

 

[skoda]

thanks guys,

in ADELXL you can click on SPECIFY DUT, this is what you mean haykding ? I try it few times, but I dont know how to exactly use it correct.

My last opinion is that you need a symbol of circuit you want to test and find him in this menu.

 

[haykding]

thanks guys,

in ADELXL you can click on SPECIFY DUT, this is what you mean haykding ? .

To be honest I haven't used that software so I don't know the details. Just use the documentation and you can find the solution.

 

[skoda]

Please, anybody has some experience with ADEXL DUT? I think I find the way how to use it, but my simulation result isn't clear.

So far I find some note ( http://wikis.ece.iastate.edu/vlsi/index.php/MonteCarlo_Simulations_using_ADE_XL ), where is said that you can set DUT only in Mismatch case not Process.

 

[beetwee]

I never used that specific option in ADEXL, but it should be easy to find it out yourself:
- what does the documentation say (click help in that particular menu).
- Test it out yourself with a simple circuit (e.g. only 1 diode connected transistor) and do seperate runs for mismatch and process.