Simulation corrected sensitivity

Abstract

A process and implementing computer system (13) for optimally sizing elements of an integrated circuit includes determining actual arrival times and required arrival times (403) for processed signals at all nodes within the integrated circuit and determining the slack or difference (405) between arrival and required times for each node. If the actual arrival time for a particular node is after the time required to meet a predetermined design constraint of the node (407), a determination (411) is made regarding the effect of that element on the nodal slack for an incremental increase in the size of that element. Thereafter an element is selected (413) for sizing increase (415) in accordance with a weighting function and the process is repeated until all of the nodes in the integrated circuit have positive slack times (407, 409). One method of accomplishing a timing analysis step (303) includes an analytical circuit simulation technique (1000-1015) in which circuit 'I-V' characteristics are more precisely represented with a power series (1006) including a plurality of regional segmental approximations (901-907). Another method of timing analysis includes an equivalency methodology (1501-1513) of translating passive transistors to equivalent RC networks (801). In the overall optimization process, a method is provided (1701-1715) for automatically correcting transistor predicted sensitivities based upon a correction factor (1713). A multi-model timing method (1601-1619) is also illustrated (1601-1619) for synergistically combining fast and accurate circuit timing models to optimize the speed and accuracy of the design process itself while remaining within an accuracy threshold.