Probabilistic crosstalk delay estimation for ASICs

The crosstalk delay caused by capacitive coupling between wires on a chip is investigated by using a statistical approach and circuit simulations. Two metrics are introduced in order to evaluate an impact of the crosstalk delay on timing design in advance. The first is probabilistic coupling rate (CPR), which can be obtained by the short segment model of the aggressors. Then, the CPR roughly obeys normal distribution and its standard deviation is determined by the slew time of the victim along with the number of aggressor segments. The second is crosstalk delay normalized by the original delay without crosstalk, Δt_pd/t_pd. The Δt_pd/t_pd is equal to 2*CPR at the maximum, and CPR on average, regardless of victim length. The two metrics in conjunction with empirical slew distribution allows us to set the appropriate crosstalk delay budget, at the prelayout stage, for reducing the possibility of the crosstalk violation found in the postlayout verification process.