Return path inductance in measurements of package inductance matrixes

Circuit theory is applied to derive a transformation to move the reference in a partial inductance matrix from one lead to another. A package is experimentally characterized with three very different return paths to produce radically different partial inductance matrixes. These matrixes are re-normalized and shown to be equal except for the initial measurement return path. Additional measurements show that repeatability is not affected by the choice of measurement return path. Bandwidth can be affected by the measurement return path.