Automated Design of Operational Amplifiers: A Case Study

Abstract

As the number of devices which can be included on a single integrated circuit (IC) increases, the trend is to implement application specific systems in one, or a few, ICs (ASICs). The fraction of the total number of IC designs which are developed for a single application has been steadily increasing in recent years. Many board-level systems have begun to migrate toward single chip implementations, and many of these applications require analog circuits as well as digital ones. In order to be economically competitive, the time between the definition of a profitable application and completion of the design of a working ASIC chip must be minimized. Therefore, the use of computer-aided design (CAD) techniques is an absolute necessity for ASIC design. While sophisticated CAD techniques have been developed to automate the design of digital circuitry, limited progress has been made toward automating the analog circuit design task in general. For example, even for an ASIC design on which 90% of the devices are used in digital circuitry and only 10% of the devices are used in analog circuitry, the analog circuit design task might well be the limiting factor in the overall design time. Because of the sensitive economic environment for ASIC designs, any delay is extremely expensive due to the loss of potential sales.