[SOLVED] help!!-monte-carlo analysis on a comparator's offset

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erikl said:
Here's a user guide for that:
Click to expand...


Thanks. But the problem is how to simulate the offset of a latched comparator which needs 2 steps to make a decision? By dc sweep or by transient simulation? If by transient one, how to print an offset voltage?
 

xuanmulidong said:
If by transient one, how to print an offset voltage?
Click to expand...
In such case I insert an artificial offset voltage (parametrized vdc source) in series with one of the inputs, then run the transient simulations sweeping the offset voltage parameter between the expected values (which you can calculate from values published in your PDK, using mismatch values depending on your W*L values (Pelgrom) and design symmetry). For a first estimation, I'd use ±10mV.
 



Thanks erikl.

Yes, by trying diferent artificial offset voltage, the minimum offset voltage could be found. But I need a picture like this: https://obrazki.elektroda.pl/46_1258984315.gif. In transient monte-carlo analysis, with big enough differential inputs, the outputs wil be turned over. But how can I catch the points , the offsets, when outputs are turned?
 

xuanmulidong said:
In transient monte-carlo analysis, with big enough differential inputs, the outputs wil be turned over. But how can I catch the points , the offsets, when outputs are turned?
Click to expand...
By increasing the value of the artificial offset voltage source you could find out when this effect occurs.

xuanmulidong said:
But I need a picture like this: https://obrazki.elektroda.pl/46_1258984315.gif.
Click to expand...
I don't know if this is possible within ADE tools. You could transfer your MC results into an excel sheet. This is a bit tedious, but it works.
 
You can find a good tutorial at the followink link.

https://www.designers-guide.org/Analysis/comparator.pdf

In case to extract statistic parameter define a calculator expression with cross and value functions to determine offset value. Decrease the input speed of signals and apply full speed clock the you do not miss input voltage difference where output changes state.

Erdogan
 


offset data can be obtained by .meas command in monte-carlo analysis, and be processed by excel to print the picture I need.
Anyway, erikl, it does work!
 

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