THERMAL NOISE LIMITED MINIMAL TURN-ON ENERGY OF AN INVERTER.

The development of digital integrated circuits is directed toward the minimization of energy required to perform an elementary logical operation (inverter turn-on energy). For presently available circuits this energy is of the order of 0. 1 pJ. The paper discusses the physical limitations for the minimal turn-on energy of an inverter, resulting from the existence of thermal noise. Arbitrary digital circuits are considered, along with MOS and CMOS circuits. The initial assumptions follow those of K. U. Stein. It is shown that these idealized assumptions results in minimal turn-on energy for elementary logical operation a few times greater than the values calculated for realistic integrated circuits. Estimated values of minimal energy fall between 4 multiplied by (times) 10**31**1**8 and 4 multiplied by (times) 10**31 **1**7 J. Numerical calculations have been estimated by simple analytical formulas allowing fast determination of minimal turn-on energy for an arbitrary integrated circuit.