Sizing of dual-VT gates for sub-VT circuits

Abstract

This paper presents a novel method to improve the performance of sub-threshold (sub-VT) gates in 65-nm CMOS technology. Faster transistors with a lower threshold voltage are introduced in the weaker network of a gate. It is shown that the employed method significantly enhances the reliability and performance of the gate, with an additive advantage of a lower area cost compared to traditional transistor sizing. Extensive Monte-Carlo simulations are carried out to verify the proposed optimization technique. The simulation results predict that the NAND3 and NOR3 testbench shows a 98% higher noise margin. Furthermore, the inverter and NAND3 gates show an speed improvement of 48% and 97%, respectively.