†Department of Mechanical and Electronic Engineering,

We propose an efficient Spice-oriented design algorithm of amplifies for attaining both the DC maximum gains and the low power consumptions. Our optimization algorithm is based on a well-known steepest descent method combining with nonlinear programming, which is realized by equiva-lent RC circuits composed of ABMs (analog behavior mod-els) of Spice. The optimum parameters are given by the equilibrium points of the transient analysis. We show our Spice-oriented optimization algorithm using the sensitivity circuits in section 2, and the interesting illustrative examples are shown in section 5. section 1