Low-power analog/RF circuit design based on the inversion coefficient

This paper discusses the concept of the inversion coefficient as an essential design parameter that spans the entire range of operating points from weak via moderate to strong inversion, including velocity saturation. Several figures-of-merit based on the inversion coefficient, especially suitable for the design of low-power analog and RF circuits, are presented. These figures-of-merit incorporate the various trade-offs encountered in analog and RF circuit design. The use of the inversion coefficient and the derived figures-of-merit for optimization and design is demonstrated through simple examples. Finally, the simplicity of the inversion coefficient based analytical models is emphasized by their favorable comparison against measurements of a commercial 40-nm bulk CMOS process as well as with simulations using the BSIM6 model.