A Layout Design System for Analog Custom LSIs

This paper describes a layout design system for analog custom LSIs with an error-free architecture. Analog LSI layout is dependent on the designer's skill and know-how because of parasitic effects peculiar to analog signal processing. Analog standard cell or linear array approaches have been proposed to reduce design time and cost, but they are semi-custom approach insufficient to cope with various analog functions. In this newly developed custom-design system, a formal description language CSL (Circuit and Layout Specification Language) have been introduced, which is capable of defining a circuit and giving analog layout specifications. The system compiles design data of the CSL form, creates various device-shapes, and completes a layout design with no violation of design rules, electrical rules and analog layout specifications, supported by analog-oriented placement, routing and compaction algorithms. At present, this system is practically used, and layout design cost and time have been reduced to one third compared with a conventional design method.