Esaki (tunnel)-diode logic circuits

The Esaki diode is a potentially low-cost, high-speed, two-terminal device exhibiting a short-circuit stable, negative resistance over a portion of its volt - ampere characteristic. Under suitable bias and loading conditions, Esaki-diode circuits can perform threshold logic and binary memory functions and can provide power gain when switched. The authors show several appropriately-biased diodes resistively coupled together such that bistable operation is obtained. The three-phase pulse-clock system shown maintains unilateral flow of information and also serves as an unconditional reset of the corresponding logic blocks. Transfer of information occurs during the period of overlap of adjacent clock pulses where the overlap is longer than the propagation time of the information. The propagation time is a function of the reactances associated with the circuit. The inclusion of reactive components in the coupling networks to provide temporary storage of information during switching eliminates the need for overlapping clock pulses. The capabilities of the various types of coupling will be discussed, and some quantitative results will be given in the presentation.