Clock skew optimization for peak current reduction
ISLPED '96 Proceedings of the 1996 international symposium on Low power electronics and design
Clock Skew Optimization for Peak Current Reduction
Journal of VLSI Signal Processing Systems - Special issue on high performance clock distribution networks
Useful-Skew Clock Routing with Gate Sizing for Low Power Design
Journal of VLSI Signal Processing Systems - Special issue on high performance clock distribution networks
Vector Transfer by Self-Tested Self-Synchronization for Parallel Systems
IEEE Transactions on Parallel and Distributed Systems
| Hi-index | 0.01 |
We propose a new approach for optimizing clock trees, especially for high-speed circuits. Our approach provides a useful guideline to a designer, by user-specified parameters, and three of these tradeoffs are provided in this paper. (1) First, to provide a "good" tradeoff between skew and wire length, a new clock tree routing scheme is proposed. The technique is based on a combination of hierarchical bottom-up geometric matching and minimum rectilinear Steiner tree. Our experiments complement the theoretical results. (2) For high-speed clock distribution in the transmission line mode (e.g., multichip modules) where interconnection delay dominates the clock delay, buffer congestion might exist in a layout. Using many buffers in a small wiring area results in substantial interline crosstalks as well as wirability, when the elongation of the imbalanced subtrees is necessary. Placing buffers evenly (locally or globally) over the plane at the minimum impact on wire length increase helps avoid buffer congestion and results in less crosstalk between clock wires. Thus, an effective technique for buffer distribution is proposed. Experimental results verify the effectiveness of the proposed algorithms. (3) Finally, a postprocessing step constraining on phase-delay is also proposed. The technique is based on a combination of hierarchical bottom-up geometric matching and bounded radius minimum spanning tree. The proposed algorithm has an important application in MCM clock net synthesis as well as VLSI clock net synthesis.