Wire-sizing optimization with inductance consideration using transmission-line model

Because of the inaccuracy bf the Elmore delay model and its inability to ha ndle inductance, it is necessary to use a more accurate delay model in mire -sizing optimization. This paper presents continuous wire-sizing optimizati on by using a three pole based delay model. Our work is focused on exponent ial wire shape f(x) = ae(-bx), i.e., me determine a and b such that either delay or area is minimized. Fringing Capacitance and inductance, which have been neglected in previous work on mire sizing, are taken into considerati on in the delay model, Expressions invoked in calculating all three poles a re derived with the help of the Picard-Carson method. Since these expressio ns are all analytical, the delay calculation is very efficient. In our expe riments, the delay model is found to be far more accurate than the Elmore d elay model, We also observe that in determining the optimal shape that mini mizes delay, the Elmore delay model performs as well as our delay model. Ho wever, in determining the optimal shape that minimizes area subject to a de lay bound, the Elmore delay model performs much worse than our delay model.