Noise Propagation and Statistic Variability in MOSFETs Using Probability Density Functions

Probability density functions using stochastic methods [1][2] are shown to be an effective tool in the context of MOSFET noise and variability modeling. These methods are employed here in the context of the charge-based EKV MOSFET model [3][4]. As an example, a Gaussian noise density function applied at the gate or the source of a MOSFET causes a corresponding drain current noise density function, which may be expressed analytically as a function of inversion coefficient only. The same expression may be used to model drain current variability due to MOSFET parameters such as threshold voltage. Furthermore, the method is extended to variations of quantities such as transconductance and transconductance-to-current ratio. The method shows promise in variability modeling of MOSFETs and may complement traditional approaches [5][6][7].