A tabular source approach to modelling and simulating device and circuit noise in the time domain



Simulation of device and circuit noise at low frequencies is often carried out as part of a small-signal ac analysis. Moreover, circuit simulators with rf analysis capabilities usually specify circuit performance in terms of S parameters and model high-frequency noise in terms of noise waves and correlation matrices. It is also unusual to find circuit simulators that extend noise simulation to the time domain. This is particularly true for software packages developed from SPICE 2g6 or 3f5. This paper introduces a simple tabular noise source technique, which adds time-domain noise to semiconductor device models and integrated circuit macromodels. The proposed technique is suitable for use with any general purpose circuit simulator. To demonstrate the power of the suggested approach the text describes time-domain noise extensions to the SPICE diode, BJT, JFET, MOSFET and MESFET models. These noise extensions have been implemented and tested with the ‘Quite universal circuit simulator’ (Qucs). Copyright © 2011 John Wiley & Sons, Ltd.