Design methodology for ultra low-power analog circuits using next generation BSIM6 MOSFET compact model

Abstract

The recently proposed BSIM6 bulk MOSFET compact model is set to replace the hitherto widely used BSIM3 and BSIM4 models as the de-facto industrial standard. Unlike its predecessors which were threshold voltage based, the BSIM6 core is charge based and thus physically continuous at all levels of inversion from linear operation to saturation. Hence, it lends itself conveniently for the use of a design methodology suited for low-power analog circuit design based on the inversion coefficient (IC) that has been extensively used in conjugation with the EKV model and allows to make simple calculations of, for example, transconductance efficiency, gain bandwidth product, etc. This methodology helps to make a near-optimal selection of transistor dimensions and operating points even in moderate and weak inversion regions. This paper will discuss the IC based design methodology and its application to the next generation BSIM6 compact MOSFET model.