Synchronous clocking schemes for large VLSI systems

Recently a novel clock distribution scheme called branch-and-combine (BaC) has been proposed. The scheme guarantees constant skew bound irrespective of the size of the clocked network. It utilizes simple nodes to process clock signals. The paper uses a VLSI model to compare the properties of the new scheme to those of the well established H-tree approach. Our study considers clocking 2-D processor meshes of arbitrary sizes. We evaluate and compare the relevant parameters of both schemes in a VLSI layout context. We show that for each BaC network, there is a certain threshold size after which it outperforms the corresponding tree network. We utilize parameters such as clock skew, link costs, node costs and area efficiency as the basis for comparison