Methods for Nominal Analog Circuit Synthesis

Abstract

To understand fully the rationale behind our nominal approach to the synthesis of high-performance analog cells, it is important to discuss the existing attempts to automate analog design and the shortcomings of these attempts. In Section 1.3 we presented a simplified view of the mixed analog/digital design process, and highlighted the cell design step as the focus of our design automation work. In this chapter we discuss four general techniques that have been used to automate the cell design step: layout-based design automation, which attempts to build a circuit by snapping together pre-designed cells or portions of cells; artificial intelligence, which has used circuit design as a test-bed for general purpose problem solving techniques; simulationbased optimization, which attempts to improve circuit performance by using detailed circuit simulation within a general purpose optimization framework; and, equation-based synthesis, which uses designer-supplied expertise to achieve circuit performance specifications by determining cell topology, sizing and biasing. These approaches are important because they underlie our own work and have substantially influenced its evolution.