PSpice Advanced Analysis: Sensitivity

Sensitivity analysis is a method of testing how the output or outcome of each component or model changes when one or more input variables are modified.  

Sensitivity analysis can help identify the most influential factors, the range of outcomes, the trade-offs and interactions between variables, which components have parameters critical to the measurement goals of your circuit design and the optimal solutions for a given objective or constraint. 

In a flow, we can use Sensitivity to identify the sensitive components, then export the components to Optimizer to fine-tune the circuit behavior. 

Sensitivity displays the absolute sensitivity or the relative sensitivity of a component. 

Absolute sensitivity is the ratio of change in a measurement value to a one-unit positive change in the parameter value. For example: There may be a 0.1V change in voltage for a 1 Ohm change in resistance. 

Relative sensitivity is the change in a measurement based on one percent positive change of component parameter value. For example: For each 1 percent change in resistance, there may be a 2 percent change in voltage. 

Sensitivity requires: 

• Circuit components that are Advanced Analysis-ready with their tolerances specified. 
• A circuit design, that is working and can be simulated in PSpice. 

• Measurements set up in PSpice.

Understanding the Sensitivity Results: 

The results are displayed in the Parameters and Specifications tables as shown above, according to the selected measurement. 

Sensitivity displays results in two tables for each selected measurement: 

• Parameters table
  • Parameter values at minimum and maximum measurement values.
  • Absolute / Relative sensitivities per parameter.
  • Linear / Log bar graphs per parameter.

• Specifications table
  • Worst-case min and max measurement values.

Watch a detailed video here