On the common-emitter breakdown voltage of bipolar junction transistors

Abstract

In bipolar junction transistors, it was believed that the common emitter breakdown voltage can be derived from the equation α F M = 1, where M is the collector-base multiplication factor, and α F is the static gain factor. When this condition holds, the collector current rises steeply and it is limited by the external resistance and the capability of the power supply or the device is destroyed. However, the common-emitter current-voltage characteristics with the base open can also be derived from α F M = 1. In the common-emitter configuration with the base open, the I− V output characteristics show that the collector current is finite. In this paper we resolve the conflict of using α F M = 1 and derive the output characteristics and the breakdown condition on a rigorous physical basis.