Mixed signal design via geometric programming

Mar Hershenson
Barcelona Design

In this talk present a method for optimizing and automating component and transistor sizing for CMOS analog circuits. We observe that a wide variety of performance measures have a special form, i.e., they are posynomial functions of the design variables. As a result, circuit design problems can be posed as geometric programs, a special type of convex optimization problem for which very efficient global optimization methods have recently been developed. The synthesis method is therefore fast, and determines the globally optimal design; in particular the final solution is completely independent of the starting point (which can even be infeasible), and infeasible specifications are unambiguously detected. Also, because the method is very efficient, in practice it can be used to carry out robust designs and quickly explore the design space. We will present practical design examples: clock generation phase-locked loops and pipeline ADC converters.