To protect against modeling limitations in considering design and electrical complexities, as well as variability, early and late signal propagation times in static timing analysis are often made pessimistic by addition of extra guard bands. However, these forced early-late splits introduce excessive and undesired pessimism. To this end, common path pessimism removal (CPPR) eliminates guaranteed redundant pessimism during timing analysis. This session aims to highlight the importance of CPPR during timing analysis, as well as explore novel methods for fast CPPR from the top performers of the TAU 2014 timing contest.

To margin against modeling limitations in considering design and electrical complexities (e.g., crosstalk coupling, voltage drops) as well as variability (e.g., manufacturing process, environmental), "early" and "late" signal propagation delays in static timing analysis are often made pessimistic by addition of extra guard bands. While these forced "early-late splits" provide desired margins, the splits applied across the entire design introduce excessive and undesired pessimism. To this end, "common path pessimism removal (CPPR)" eliminates the redundant pessimism during timing analysis.

In this paper we review the prior art and recent advances in the area of standard cell modeling for delay and noise analyses, suggest a taxonomy of different cell models, and discuss their strengths and weaknesses. We also discuss challenges in cell modeling for delay and noise analyses arising in new submicron process nodes.

In This work we present a robust and efficient methodology for crosstalk-induced delay change analysis for ASIC design styles. The approach employs optimization methods to search for worst aggressor alignment, and it computes crosstalk induced delay change on each stage considering an impact on downstream logic. Computational efficiency is achieved using pre-characterized current models for drivers and compact macromodels for interconnect. The proposed methodology has been implemented in a commercial noise analysis tool. Experimental results obtained on industrial designs demonstrate high accuracy and reduced pessimism of the proposed methodology.