THMA10: A commercial implementation of modal calibration to improve GSSG Calibration

Presentation Abstract
Differential designs are commonplace in the industry, for reasons including odd-order harmonic cancellation, good emissions performance, tolerance of process variance, and larger swing even on low-voltage processes. However, the factors which make tightly coupled differential designs attractive for the designer also make the acquisition of accurate S-parameter data challenging, due to incompatibility with the uncoupled representation assumed by conventional calibration algorithms. An approach to use the symmetry of the problem to ameliorate this has been proposed, and is now available in a commercial calibration package. This implementation is described, and the benefits arising from it discussed with real examples.