Non-quasi-static effects in saturated bipolar circuits

Abstract

An non-quasi-static (NQS) model accounting for intrinsic carrier propagation delays in both B/E and B/C junctions is implemented in the ASTAP circuit simulator to evaluate the impact of non-quasi-static effects in saturated bipolar circuits. It is shown that while the extra delay introduced by the NQS effects during the turn-on transition is primarily due to the normal mode B/E NQS time constant, the more severe NQS delay in the turn-off transition is caused mainly by the removal of the saturation over-drive charges and the longer inverse mode B/C NQS time constant.