eldo_user

Examples
Example 19—DC Mismatch Comparison with Monte Carlo Analysis
Example 19—DC Mismatch Comparison with
Monte Carlo Analysis
Netlist file: dcmismatch_contributors.cir
This example shows how to use the DCMISMATCH analysis, and compares its results to an
equivalent Monte Carlo analysis. You can refer to the .chi output file and look for the
DCMISMATCH and Monte Carlo results respectively.
Particularly, from the DCMISMATCH results, devices M1 and M2 are primarily responsible
for the output offset distribution, whereas M17 and M16 have the greatest impact on power
consumption.
These results are confirmed by the fully non-linear .MC sensitivity analysis. You can also refer
to the example dcmismatch_vs_mcsens.cir which shows how to compare the results of the two
analyses using some simple ECL (Eldo Control Language) code.
Summary of Eldo commands used in this example:
• .DCMISMATCH—DC mismatch analysis.
• .MC—Monte Carlo analysis.
• .ALTER—Simulation rerun.
• .EXTRACT—Extract characteristics from the simulator results.
Netlist Explanation
.EXTRACT DC LABEL=offset v(out)
The above line specifies to extract the output offset voltage.
.EXTRACT DC LABEL=power -i(vdd)*v(vdd)
The above line specifies to extract the DC power consumption.
.alter
.DCMISMATCH nsigma=1
.extract dc label= dcm_offset dcm(offset)
.extract dc label= dcm_power dcm(power)
The above lines rerun the same simulation using a DC mismatch analysis.
.alter
.mc 10000
.extract mc label=mc_offset mcstd(offset)
.extract mc label=mc_power mcstd(power)
The above lines rerun the same simulation using a Monte Carlo analysis. The Monte Carlo
sensitivity is run automatically.
1316
Eldo® User's Manual, 15.3