Automatic Modeling of Analog Circuits in a Portable Electrical Analysis CAD Framework

The concept of automatic AC modeling of analog integrated circuits is demonstrated via selected examples. A new self-contained symbolic analysis tool, ASAP, has been developed to this end. It is able to automatically compute both exact and simplified expressions for any of the system functions associated to analog circuits. Efficiency, ability to manage complexity and portability are the fundamental goals of ASAP. Efficiency is demonstrated via the calculation of an exact expression (7533 terms) of the frequency dependent differential gain of a Miller opamp in /6.2s CPU-time. The level of complexity is illustrated by analyzing a folded-cascode opamp with a MOS transistor model containing seven elements (resulting in 97953 terms). Portability is guaranteed by the use of the C language.