An automated design tool for analog layouts

Abstract

In this paper, a layout synthesis tool for the design of analog integrated circuits (ICs) is presented. This tool offers great flexibility that allows analog circuit designers to bring their special design knowledge and experiences into the synthesis process to create high-quality analog circuit layouts. Different from conventional layout systems that are limited to the optimization of single devices, our layout generation tool attempts to optimize more complex modules. This tool includes a complete tool suite that covers the following three major analog physical designs stages. 1) Module Generation: designers can develop and maintain their own technology- and application-independent module generators for subcircuits using an in-house developed description language. 2) Placement: a two-stage placement technique, tailored for the analog placement design, is proposed. In particular, this placement algorithm features a novel genetic placement stage followed by a fast simulated reannealing scheme. 3) Routing: the minimum-Steiner-tree-based global routing is developed, and it is actually integrated into the placement procedure to improve reliability and routability of the placement solutions. Following the global routing, a compaction-based constructive detailed routing finally completes the interconnection of the entire layout. Several testing circuits have been applied to demonstrate the design efficiency and the effectiveness of this tool. Experimental results show that this new layout tool is capable of producing high quality layouts comparable to those manually done by layout experts but with much less design time.