C mosfet model for analogue circuit simulation employing process-empirical parameters

In the design of linear MOS integrated circuits, transistor models must be accurate in the saturation region, but the excellent fitting in the linear region obtainable with sofisticated physical models and modelling of short-channel effects are less important. Besides, in many of the available MOST models, the so-called physical parameters are, in practice, evaluated from fitting procedures on measured device characteristics, and so a fully empirical point of view may as well be adopted in chosing model equations. By exploiting these considerations, better trade-offs between accuracy and ease of parameter acquisition can be obtained. In the paper we present a simple empirical MOST model which accounts for mobility reduction and channel-length modulation in MOS devices with dimensions suitable for analogue applications. It is proved that the proposed model is no less accurate in the CAD of linear circuits than other more elaborate models, but it is more simple as far as parameter acquisition is concerned. Finally, it is shown that the model provides differential parameters which are reasonably accurate, and that it can be successfully employed in the CAD of MOS analogue integrated circuits.