Active noise cancellation using aggressor-aware clamping circuit for robust on-chip communication

As the IC process technology scales the on-chip wiring network becomes denser. Increasing aspect ratios of the on-chip interconnects lead to higher coupling capacitances and ultimately higher cross-talk noise, which degrades signal integrity. In this paper we propose a clamping circuit for on-chip busses, which clamps a victim wire in an on-chip bus based on the states of its immediate aggressors. These clampers help the driver of the victim wire in draining the charge, which is induced due to cross-talk between aggressors and victim wires. This helps in decreasing the cross-talk peak noise and also the delay variability (referred to as delay noise). Simulation results for a 10 mm long communication bus (parallel wires) laid at minimum pitch in 0.13 μm CMOS technology show that a reduction of 30%(17.6%), 37%(27.2%) and 26%(65.8%) in cross-talk peak noise amplitude (delay noise) is observed for point to point, parallel repeater inserted and staggered repeater inserted respectively when only immediate neighbours are considered (1^st order). Furthermore the aggressor-aware clamper is very effective in avoiding glitches, which may occur when more aggressors, in addition to the immediate ones are also switching simultaneously in the same.