Fast low-power driver and Schmitt trigger using GaAs MESFET and tunnel diode

Attempts to develop high-speed logic circuits using tunnel diodes during the 1960s were not successful in connection with difficulties related to cross-talk. However, there exist currently promising approaches for such developments. These approaches involve an employment of fast field effect transistors. The excellent input-output insulation and the eminent switching properties of the MESFETs are combined with the special current-voltage characteristics of the tunnel diode. The obtained circuits have Schmitt trigger characteristics and a transfer function with hysteresis. Lehovec (1979) has shown that an ultra-fast low-power inverter can be designed with a GaAs enhancement mode FET-tunnel diode. The present investigation is concerned with the design of a driver circuit having Schmitt trigger characteristics, taking into account also the use of the circuit as memory cell. The considered circuit makes it possible to obtain very short switching times and a high driver power for capacitive loads.