Mixed-Vth (MVT) CMOS circuit design methodology for low power applications

Dual threshold technique has been proposed to reduce leakage power in low voltage and low power circuits by applying a high threshold voltage to some transistors in non-critical paths, while a low-threshold is used in critical path(s) to maintain the performance. Mixed-V_th (MVT) static CMOS design technique allows different thresholds within a logic gate, thereby increasing the number of high threshold transistors compared to the gate-level dual threshold technique. In this paper, a methodology for MVT CMOS circuit design is presented. Different MVT CMOS circuit schemes are considered and three algorithms are proposed for the transistor-level threshold assignment under performance constraints. Results indicate that MVT CMOS design technique can provide about 20% more leakage reduction compared to the corresponding gate-level dual threshold technique