Tunnel-Diode Switching Time and Its Dependence on Diode Nonlinearities

Switching time of a tunnel diode is studied without resorting to the usual straight-line approximations for the diode characteristic. It is shown that switching time is dependent upon some average of the nonlinearities in the circuit, whereas dependency upon the detailed behavior of these nonlinearities is implied in the piecewise-linear approach. In view of the analysis in this paper it is apparent that the magnitude of the negative resistance of the diode is of no consequence in determining switching time. An expression for switching time is developed in the form of a figure-of-merit multiplied by a power series in the threshold to trigger-magnitude ratio. The coefficients of the series are explicitly defined and essentially insensitive to variations in load resistance and diode characteristic. For the accuracy usually required, the series may be truncated after three terms. With a constant threshold to trigger-magnitude ratio, the figure-of-merit multiplier provides a simple means of evaluating the switching time. The series representation for switching time can be used in the selection of a load line for a circuit or as a guide in the choice of diodes for a specific application.