Specifying Analytical Model Types

You can model parametric and statistical variation in circuit behavior in Star Hspice by using:

• The .PARAM statement. Use to investigate the performance of a circuit as specified changes in circuit parameters are made. See Specifying Simulation Input and Controls for details of the .PARAM statement.
• Temperature Variation Analysis. The circuit and component temperatures are varied and the circuit responses compared. The temperature-dependent effects of the circuit can be studied in detail.
• Monte Carlo Analysis. The statistical standard deviations of component values are known. Use for centering a design for maximum process yield, or for determining component tolerances.
• Worst Case Corners Analysis. The component value limits are known. Automates quality assurance for basic circuit function for process extremes, quick estimation of speed and power trade-offs, and best case and worst case model selection through parameter corners library files.
• Data Driven Analysis. Use for cell characterization, response surface, or Taguchi analysis. See Performing Cell Characterization. Automates cell characterization, including timing simulator polynomial delay coefficient calculation. There is no limit on the number of parameters simultaneously varied or number of analyses to be performed. Convenient ASCII file format for automated parameter value generation. Can replace hundreds or thousands of Star-Hspice runs.

Yield analyses are used to modify DC operating points, DC sweeps, AC sweeps, and transient analysis. They can generate scatter plots for operating point analysis and family of curves plots for DC, AC, and transient analysis.

The .MEASURE statement in Star-Hspice is used with yield analyses, allowing you to see distributions of delay times, power, or any other characteristic described with a .MEASURE statement. Often, this is more useful than viewing a family of curves generated by a Monte Carlo analysis. When the .MEASURE statement is used, a table of results is generated as an .mt# file, which is in readable ASCII format, and can be displayed in AvanWaves. Also, when .MEASURE statements are used in a Monte Carlo or data driven analysis, the Star-Hspice output file includes calculations for standard statistical descriptors:

Mean
Variance
Sigma
Average Deviation