Supply voltage degradation aware analytical placement

Abstract

Increasingly significant power/ground supply voltage degradation in nanometer VLSI designs leads to system performance degradation and even malfunction. Existing techniques focus on design and optimization of power/ground supply networks. In this paper, we propose supply voltage degradation aware placement, e.g., to reduce maximum supply voltage degradation by relocation of supply current sources. We represent supply voltage degradation at a P/G node as a function of supply currents and effective impedances (i.e., effective resistances in DC analysis) in a P/G network, and integrate supply voltage degradation in an analytical placement objective. For scalability and efficiency improvement, we apply random-walk, graph contraction and interpolation techniques to obtain effective resistances. Our experimental results show an average 20.9% improvement of worst-case voltage degradation and 11.7% improvement of average voltage degradation with only 4.3% wirelength increase.