Automation of Analog Design Procedures

Advances in VLSI technology nowadays allow the realization of complex circuits and systems. ASIC’s are moving towards the integration of complete systems on one chip, including both digital and analog parts. The use of computer-aided design tools has become indispensable to reduce the design time and cost. But whereas for digital VLSI a lot of design tools, methodologies and architectures have been developed, resulting now in complete digital silicon compilers, the first analog design tools and methodologies are just being introduced [1–7]. Most of the design is still carried out manually by analog experts, deriving simplified circuit expressions by hand and iteratively using numerical circuit simulators (such as SPICE) by trial and error. This explains why the analog part — though relatively 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 high frequencies, low noise and low distortion. Besides, due to the hand design and hand layout, errors frequently occur in the small analog section, leading to several reruns.