Introduction to Analog Design Automation

Abstract

Advances in VLSI technology nowadays allow the realization of complex integrated electronic circuits and systems. Application-specific integrated circuits (ASICs) are moving towards the integration of complete systems. These microsystems include both digital and analog parts on a single chip. At the same time, the use of computer-aided design (CAD) tools has become indispensible to reduce the total design time and cost. For digital VLSI, several methodologies and design tools have been developed in the past, resulting in complete digital silicon compilers [GAJ_88]. The first analog design tools and methodologies, however, are just now being introduced [DEG_87c, GIE_90a, HAR_89b, KOH_90, etc.]. Most of the design is still carried out manually by analog experts. These experts derive simplified circuit expressions by hand, iteratively use numerical circuit simulators by trial and error and handcraft the layout. This explains why the analog part — though usually small in area — takes more and more of the overall design time and cost of the present mixed analog-digital chips. This is especially true in high-performance applications, requiring for example high-frequency performance, high precision, low noise and/or low distortion. Besides, due to the hand design and hand layout, errors frequently occur in the small analog section, leading to several reruns. This delay cannot be tolerated in most applications where the time to market is critical for profit.