Simultaneous Vt selection and assignment for leakage optimization

This paper presents a novel approach for leakage optimization through simultaneous V/sub t/ selection and assignment. V/sub t/ selection implies deciding the right value for V/sub t/ and assignment implies deciding which gates should be assigned which threshold value. The proposed algorithm is a general mathematical formulation that can be trivially extended to multiple threshold voltages (more than two). Traditional leakage optimization strategies either assume the prespecification of threshold values or are good only for two thresholds. The presented formulation is based on a linear programming approach under the piecewise linear approximation of delay/leakage vs threshold curves. The algorithm was incorporated in SIS. Experimental results indicate that on some benchmarks having more that two thresholds was beneficial for leakage.