Understanding the behavior of RTD-loaded NMOS inverter through compact-form analysis

Abstract

Abstract Resonant-tunneling diodes (RTDs) find a wide variety of applications in oscillators, digital circuits, and latches due to their reduced circuit complexity, low power, and high speed. Since the inverter is the main building block in digital design, in this paper, the analysis of the RTD-loaded NMOS inverter is addressed quantitatively with its static and dynamic characteristics investigated and compared with that of the conventional static CMOS inverter. Specifically, compact-form expressions are derived for the critical points of the voltage-transfer characteristics (VTC), the low-to-high, and the high-to-low propagation delays along with the fan-out. Also, the static- and dynamic–power consumption are investigated and equations are derived for them. The results obtained from this analysis can be generalized to RTD-MOS logic-circuit family in which the pull-down network contains properly connected and appropriately sized NMOS transistors and the pull-up network is the RTD device. The results of the quantitative analysis are discussed and verified by comparison with the simulation results using the Berkeley predictive-technology model (BPTM) of the 45 nm CMOS technology with a power-supply voltage of 1 V.