synthesis of low power clock trees for handling power-supply variations
The International Symposium on Physical Design (ISPD) 2010 contest presents the challenge of synthesizing clock distribution networks that are tolerant to severe power-supply and wire-width variations. In particular, a robust clock network should satisfy the local clock skew (LCS) constraint, i.e., the clock skew between any pair of sequential elements that are closer than a user-specified distance is below a user-specified limit, even in the presence of variations. In this paper, we identify a few factors that help in tolerating these variations in clock trees. Our proposed clock tree router uses a two-stage flow to construct low-power clock trees for which the LCS constraints are met. Our clock tree router has been tested on ISPD'10 contest benchmark circuits. Extensive Monte-Carlo simulations showed that low power clock tree solutions could effectively handle variations, even when we imposed more stringent conditions in the experimental setup.
clock trees variations physical design vlsi cad