Power partition and emitter size optimization for bipolar ECL circuit

An automated approach for optimizing the performance of a bipolar ECL circuit is described. A quadratic equation representing an approximate surface is used to express the circuit delay in terms of the power partition and current densities in the current-switch and emitter-follower stages. During the iteration of the optimization process, the optimum obtained from each approximate surface is used as the nominal point for the next iteration. As the nominal point converges to the optimal, the approximate surface converges to a section of the real optimum surface. This methodology transforms the circuit optimization into a multivariable optimization problem and is shown to provide an optimum design with circuit analysis accuracy. The design considerations for high-performance ECL circuits are also discussed