AN EXCLUSIVE-OR LOGIC-CIRCUIT BASED ON CONTROLLED QUENCHING OF SERIES-CONNECTED NEGATIVE DIFFERENTIAL RESISTANCE DEVICES

An exclusive-OR (XOR) logic circuit with a clocked supply voltage base d on the controlled quenching of series-connected negative differentia l resistance (NDR)devices is demonstrated, This controlled quenching p rocess obeys a simple rule: the NDR device with the smallest peak curr ent is always quenched first. In our present work, resonant-tunneling diodes provide the critical NDR feature, while FET's, which are integr ated with RTD's in parallel, modulate the peak currents of NDR devices . The modulation of peak currents in different NDR devices directly co ntrols the quenching sequence, and results in certain logic functions, one of which is XOR.