ABSTRACT
This chapter reviews several metrics that may be used in objective and constraint functions in physical design, used to measure circuit properties such as timing, noise, power, and temperature. It introduces the timing metrics commonly used in physical design. The chapter also reviews the classic Elmore delay and slew metric, followed by more advanced fast timing estimation metrics and the fundamentals of static timing analysis of combinational circuits. The Elmore delay of an resistance-capacitance tree has another important property: it can be proven to be the upper bound of the true 50 percent circuit delay under any input excitation. The essence of Elmore delay is the probability interpretation of the impulse response of a linear circuit. The lognormal distribution can also be used to provide a closed-form slew metric. Coupling noise is yet another unwanted side effect of the scaling in deep submicron technology, and its impact can be reduced through physical design transformations.
