Dynamic behavior of active charge in I/sup 2/L transistors calculated with lumped transistor models

In this paper, a base for further detailed I/SUP 2/L lumped modeling work is given. The lumped model is used because of its close contact with internal physical processes. Transmission line effects can be included, using multilump models. Excess minority carrier plots, which can be derived from internal node voltages, visualize very clearly the behavior of the active charge. As an example, a transient calculation is presented in which the minimum delay time is calculated. It appears that the relatively thick n-epi emitter of the inverse operated n-p-n transistor determines the switching behavior. Some measurements done with ring oscillators indicate that short ring oscillators give too optimistic delay times.