Hello,
I have spent a lot of time investigating following task:
Assume I have to perform mismatch simulations of a comparator using montecarlo anlaysis in ADE-XL. I need to collect comparator offset (dc sim) and duty cycle ( tran).
As a result I would like to have a scatter plot where on X-axis offset voltage and on Y-axis duty cycle.
I have tried several methods but without any success.
Apporach 1: I have one test withe two instances of the comparator (I1/ I2). I have a dc /transient simulation preset in single test.
Comparator I1 has stimuli for dc offset extraction, while I2 has stimuli for transient analysis ( duty cycle extraction).
I have specified instance as "Master" of CMP_TOP cell in montecarlo "Specify Inst/device" menu.
As a result on line has been created for test:
| Test | Type | Sch/Master/Subcircuit | Data |
| tst | Master | CMP_TOP | I1, I2 |
I have checked mismatch data applied for devices inside the comparator but only to see that a different set of values have been used for I1 and I2. I have looked for every possible option/setting but no way where I could specify correlation between the devices in I1 and I2.
I know for a fact that when you are defining parameter distribution for montecarlo there is a statistic block where a special syntax exists that allows to define correlation between devices/parameters.
Mismatch Correlation (Matched Devices)
The syntax of the instance or mismatch correlation statements are:
correlate dev=[list of subcircuit instances] {param=[list of parameters]} cc=<value>
correlate dev=[<wildcard_expression] {param=[list of parameters]} cc=<value>
Approach2: create 2 separate test benches + schematics and then use the same method to specify device for mc variation. Just a note that the instance name will have to be exactly the same otherwise different set of variations will be used for each setup.
I am using IC617ISR15 and MMSIM 16.1.
Question1: Is there a way in MC setup how achieve that a any occurrence of a cell inside the test bench schematic will end up having the same statics parameter variations within single mc simulation run?
Question2: Assuming I will have two test benches where the offset will be expression calculated in test1 and duty cycle in test 2. How to make a scatter plot in montecarlo sweep where on x-ais will be expression value from one test and on Y-axis value of an expression from another test?
Many thanks!
Regards Marian