Differential multiple-valued logic using resonant tunneling diodes

Differential multiple-valued logic (MVL) based on resonant tunneling diodes (RTDs) and heterojunction bipolar transistors is described. The novel gates are of the emitter-coupled current-switch type and can implement a wide range of MVL functions, including sums of products and multiple-threshold elements. One of the gates consists of diodes performing the input-thresholding functions and current switches generating the summation currents; the other consists of current switches with settable reference voltages generated by vertically integrated multiple RTDs. The thresholds can be switched to any value between zero and maximum input sum. The differential MVL is demonstrated theoretically with SPICE simulations based on device data and advanced RTD models, and experimentally with breadboard circuits.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>