Miller factor for gate-level coupling delay calculation

In coupling delay computation, a Miller factor of more than 2/spl times/ may be necessary to account for active coupling capacitance when modeling the delay of deep submicron circuitry in the presence of active coupling capacitance. We propose an efficient method to estimate this factor such that the delay response of a decoupling circuit model can emulate the original coupling circuit. Under the assumptions of zero initial voltage, equal charge transfer, and 0.5V/sub DD/ as the switching threshold voltage, an upper bound of 3/spl times/ for maximum delay and a lower bound of -1/spl times/ for minimum delay can be proven. Efficient Newton-Raphson iteration is also proposed as a technique for computing the Miller factor or effective capacitance. This result is highly applicable to crosstalk coupling delay calculation in deep submicron gate-level static timing analysis. Detailed analysis and approximation are presented. SPICE simulations are demonstrated to show high correlation with these approximations.