Robust subthreshold logic for ultra-low power operation

Digital subthreshold logic circuits can be used for applications in the ultra-low power end of the design spectrum, where performance is of secondary importance. In this paper, we propose two different subthreshold logic families: 1) variable threshold voltage subthreshold CMOS (VT-Sub-CMOS) and 2) subthreshold dynamic threshold voltage MOS (Sub-DTMOS) logic. Both logic families have comparable power consumption as regular subthreshold CMOS logic (which is up to six orders of magnitude lower than that of normal strong inversion circuit) with superior robustness and tolerance to process and temperature variations than that of regular subthreshold CMOS logic.