Variability Analysis Tool for CMOS Analog/RF Circuits: VariAnT

Commercial EDA tools offer process, voltage, and temperature (PVT) variation analyses in order to estimate the variation effects on circuit performances. However, many of them use primitive MC (random sampling) during generation of the uncertain design space, which results in excessively long simulation times (days, weeks, even months). Furthermore, users have limited access to modify some important properties (i.e. sampling method, variation type, etc.) in such tools. In this study, a comprehensive, flexible, and user-friendly SPICE based variability analysis tool (VariAnT) is presented, which exhibits four different variation analyses: Monte Carlo, Worst Case, Voltage-Temperature, and Sensitivity. The developed tool includes two enhanced sampling approaches during MC analysis: quasi-random sampling and Latin Hypercube sampling, which improves the efficiency by reducing the number of samples required for an accurate yield estimation. Furthermore, sensitivity analysis helps users to determine the most critical device(s), which is a valuable design insight to reduce the number of re-design iterations.