Analog circuit design optimization based on symbolic simulation and simulated annealing

A methodology for the automatic design optimization of analog integrated circuits is presented. A non-fixed-topology approach is realized by combining the optimization program OPTIMAN with the symbolic simulator ISAAC. After selecting a circuit topology, the user invokes ISAAC to model the circuit. ISAAC generates both exact and simplified analytic expressions, describing the circuit´s behavior. The model is then passed to the design optimization program OPTIMAN. This program is based on a generalized formulation of the analog design problem. For the selected topology, the independent design variables are automatically extracted and OPTIMAN sizes all elements to satisfy the performance constraints, thereby optimizing a user-defined design objective. The global optimization method used on the analytic circuit models is simulated annealing. Practical examples show that OPTIMAN quickly designs analog circuits, closely meeting the specifications, and that it is a flexible and reliable design and exploration tool