Charged based MOS transistor modeling in weak inversion

This paper brings in three transistor models that may be used for weak inversion design: the EKV model, the ACM model and the BSIM3v3 model. The EKV model is used in modeling of weak inversion to offer an accurate prediction of low-voltage, low-current designs. The ACM model gives equations that avoid non-physical interpolating curves between weak inversion and strong inversion region, with the intensions of modeling moderate inversion more precisely. The model is an extension of EKV model and is useful at the limits of weak inversion, where circuit will benefit from drifting into moderate inversion. As a final point the BSIM3v3 model is compared with the EKV model and a good relationship is shown. Although EKV model is considerably less complex as compared to BSIM3v3 model it is sufficiently accurate to model transistors. To demonstrate the ability for circuit analysis a transconductor is used as an example.