Cell replication and redundancy elimination during placement for cycle time optimization

Abstract

Presents a new timing-driven approach for cell replication tailored to the practical needs of standard cell layout design. Cell replication methods have been studied extensively in the context of generic partitioning problems. However, until now, it has remained unclear what practical benefit can be obtained from this concept in a realistic environment for timing-driven layout synthesis. Therefore, this paper presents a timing-driven cell replication procedure, demonstrates its incorporation into a standard cell placement and routing tool, and examines its benefit on the final circuit performance in comparison with conventional gate or transistor sizing techniques. Furthermore, we demonstrate that cell replication can deteriorate the stuck-at fault testability of circuits and show that stuck-at redundancy elimination must be integrated into the placement procedure. Experimental results demonstrate the usefulness of the proposed methodology and suggest that cell replication should be an integral part of the physical design flow complementing traditional gate sizing techniques.