An electrical optimizer that considers physical layout

Electrical performance and area improvement are important parts of the overall VLSI design task. Given designer specified constraints on area, delay, and power, EPOXY will size a circuit's transistors and will attempt small circuit changes to help meet the constraints. In addition, the system provides a flexible framework within which to evaluate the effects of different area and electrical models, as well as different optimization algorithms. Since the sum of transistor area is a better measure of dynamic power than cell area, a more accurate area model is presented. Optimization of a CMOS eight-stage inverter chain illustrates this difference; a typical minimum power implementation is 32.3% larger than the one for minimum area. The combination of a TILOS-style heuristic and augmented Lagrangian optimization algorithm yields quality results rapidly. EPOXY'S circuit analysis is from 5 to 56 times faster than Crystal.

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