FUNCTIONS AND APPLICATIONS OF MONOSTABLE-BISTABLE TRANSITION LOGIC ELEMENTS (MOBILES) HAVING MULTIPLE-INPUT TERMINALS

The MOBILE is a logic gate exploiting the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors connected in series. It has several advantages including multiple inputs and multiple functions. This paper describes the output characteristics of multiple-input MOBILE's and discusses their applications. For a two-input MOBILE, it is demonstrated that both NAND and NOR operations are possible with the appropriate control voltage. This implies the possibility of a variable function logic gate. Furthermore, the threshold logic operations for a weighted sum of input signals are demonstrated for a three-input MOBILE with a weight ratio of 4:2:1. The applications of MOBILE's in parallel processing architectures such as cellular automata and cellular neutral networks are discussed based on the above results. Circuit simulations using a simple model of resonant tunneling transistors successfully reproduce the basic characteristics of MOBILE's, and demonstrate the usefulness of MOBILE's in such applications.