BSIM3v3.2.2 MOSFET Model - The University of Texas at Dallas

Model Formulationwhere i represents the four terminals and C di and C si are the intrinsiccapacitances calculated from the quasi-static analysis. The correspondingvalues for S xpart can be derived from the fact that D xpart + S xpart = 1.In the accumulation and depletion regions, Eq. (5.3.9) is simplified asIf XPART < 0.5, D xpart = 0.4;Else if XPART > 0.5, D xpart = 0.0;Else D xpart = 0.5;5.3.4 Derivation of nodal conductancesThis section gives some examples of how to derive the nodal conductancesrelated to NQS for transient analysis. By noting that τ = RC, G tau can bederived asCGtau=τfact(5.3.11)τis given by Eq. (5.3.2). Based on Eq. (5.3.8b), the self-conductance dueto NQS at the transistor node D can be derived asdDdVxpartd⋅( G ⋅V)taudef+ Dxpart⋅VdefdG⋅dVtaud(5.3.12)The trans-conductance due to NQS on the node D relative to the node ofQ def can be derived asDxpart ⋅Gtau(5.3.13)BSIM3v3.2.2 Manual Copyright © 1999 UC Berkeley 5-7