Compact multiple-valued multiplexers using negative differential resistance devices

TL;DR: In this article, the design of the T-gate was done using a combination of resonant tunneling diodes (RTD's) and heterojunction bipolar transistors (HBT's) with the folded I-V characteristic (NDR characteristic) of the RTD's providing the compact logic implementation and the HBTs providing the gain and isolation.

Abstract: Quantum electronic devices with negative differential resistance (NDR) characteristics have been used to design compact multiplexers. These multiplexers may be used either as analog multiplexers where the signal on a single select line selects one out of four analog inputs, or as four-valued logic multiplexers where the select line and the input lines represent one of four quantized signal values and the output line corresponds to the selected input. Any four-valued logic function can be implemented using only four-valued multiplexers (also known as T-gates), and this T-gate uses just 13 devices (transistors) as compared to 44 devices in CMOS. The design of the T-gate was done using a combination of resonant tunneling diodes (RTD's) and heterojunction bipolar transistors (HBT's) with the folded I-V characteristic (NDR characteristic) of the RTD's providing the compact logic implementation and the HBT's providing the gain and isolation. The application of the same design principles to the design of T-gates using other NDR devices such as resonant tunneling hot electron transistors (RHET's) and resonant tunneling bipolar transistors (RTBT's) is also demonstrated.