Clock Buffer Polarity Assignment for Power Noise Reduction**This work is partially supported by Semiconductor Research Corporation under contract 2004-TJ-1205.

Power/ground noise is a major source of VLSI circuit timing variations. This work aims to reduce clock network induced power noise by assigning different signal polarities (opposite switchings) to clock buffers in an existing buffered clock tree. Three assignment algorithms are proposed: (1) partitioning, (2) 2-coloring on minimum spanning tree and (3) recursive min-matching. A post-processing of clock buffer sizing is performed to achieve desired clock skew. SPICE based experimental results indicate that our techniques could reduce the average peak current and average delay variations by 44% and 54% respectively. Copyright 2006 ACM.

Clock Buffer Polarity Assignment for Power Noise Reduction**This work is partially supported by Semiconductor Research Corporation under contract 2004-TJ-1205. Conference Paper