Submicron CMOS thermal noise modeling from an RF perspective

Abstract

Continuous scaling of submicron CMOS technologies will soon make low cost, wireless system-on-a-chip communication products possible. The ultimate goal of these systems is to integrate the entire RF front-end with DSP together on a single chip. One key issue to the success of this CMOS RF system LSI chip implementation is how to accurately predict circuit performance using simulators such as SPICE. This will require accurate RF AC and noise models. The latter is essential for optimizing the noise performance which will in turn lead to a low power design. Recently, several CMOS RF models have been proposed for improvement on the accuracy of AC analysis at high frequencies (Ou et al, 1998). However, the accuracy of the existing noise models is not satisfactory for submicron CMOS. In this paper, a physics-based RF thermal noise model is proposed for submicron CMOS devices with a channel thermal noise model, resulting in a nearly bias-independent noise factor /spl gamma/. This model shows good agreement with measured RF noise data across a wide range of bias conditions.