Automated Decoupling Capacitor Optimization
ANSYS SIwave PI Advisor significantly improves engineering productivity by automating decoupling capacitor selection, placement and optimization for printed circuit boards and IC packages. The underlying engine, based on sophisticated genetic algorithms, allows the specification of various constraints (capacitor price, total number of capacitors, desired network impedance, etc.) for consideration in its cost function. Accurate frequency-dependent S-parameter capacitor models are utilized during simulation. In addition, the impact of capacitor physical location and mounting technique is captured by the full-wave SIwave extraction engine.
Once optimization is complete, PI Advisor presents several decoupling schemes (each consisting of a set of capacitors) that meet the specified constraints. You can browse the schemes and export a bill of materials (BoM) for those deemed to best meet requirements. You alsocan superimpose a 3-D bar graph on the layout to indicate loop inductance values. This provides an immediate, intuitive understanding of each capacitor's effectiveness.
SimplePI Lumped Analysis
SimplePI lumped analysis provides a quick calculation to determine capacitor values and placement. This solution ascertains the lumped circuit equivalent of all the capacitors on a board or package and can be used to develop the best-candidate capacitors for a given design. In addition, lumped analysis automatically determines the best type and number of capacitors for a frequency-dependent impedance mask.