Efficient volterra series based sensitivity analysis of mildly nonlinear circuits

Sensitivity analysis is useful in comparing the quality of two different designs. It is also used to evaluate the gradient, Jacobian or Hessian matrices in analog computer aided design. In (Zhu and Opal, 2006) the authors presented a Volterra series based sensitivity analysis of mildly nonlinear circuits in the frequency domain. This sensitivity calculation can be expensive in certain circumstances because of multiple mixing effects (Zhu, 2007). In this paper, we propose the concept of nonlinear transfer matrix (NTM) to improve computational efficiency. Examples show that NTM improves the efficiency of sensitivity analysis of mildly nonlinear circuits, e.g. two orders of magnitude speedup for large circuits.