Hi Umut !

Spectre supports a mismatch correlation but I have never used in the

case you're describing. I rather used it to correlate matched devices,

i.e, force Spectre to not exceed a certain mismatch percentage between

2 subcircuits by defining a correlation parameter.

I may need to give it a go with your case but I'm offline right now.

You may give a look at the Spectre Ref manual in the meanwhile.

There is a snippet from this doc.

---

Mismatch Correlation (Matched Devices):

The syntax of the instance or mismatch correlation statement is:

correlate dev=[list of subcircuit instances] {param=[list of

parameters]} cc=<value>

where the device or subcircuit instances to be matched are listed in

the list of subcircuit

instances, and the list of parameters specifies exactly which

parameters with mismatch

variations are to be correlated.

The instance mismatch correlation statement is used to specify

correlations for particular

subcircuit instances. If a subcircuit contains a device, you can

effectively use the instance

correlation statements to specify that certain devices are correlated

(i.e. matched) and give

the correlation coefficient. You can optionally specify exactly which

parameters are to be

correlated by giving a list of parameters (each of which must have had

distributions specified

for it in a mismatch block), or specify no parameter list, in which

case all parameters with

mismatch statistics specified are correlated with the given

correlation coefficient. The

correlation coefficients are specified in the <value> field and must

be between +/- 1.0.

---

There is a good explanation of Matched Devices and Correlate

Statements in the following document as well:

http://www.designers-guide.org/Modeling/montecarlo.pdf
Once again, I'm not sure is Spectre handles your specific case. Andrew

is the best person in here to comment about it !

Riad.