Efficient AC Analysis of Oscillators using Least-Squares Methods

We present a generalization of standard AC analysis to oscillators by exploiting least-squares solution techniques. This provides an attractive alternative to the current practice of employing transient simulation for small signal analysis of oscillators. Unlike phase condition based oscillator analysis techniques, which suffer from numerical artifacts, the least-squares approach of this paper results in a robust and efficient oscillator AC technique. We validate our method on LC and ring oscillators, obtaining speedups of 1-3 orders of magnitude over transient simulation, and 4-6times over phase-condition-based techniques