This section describes how to use noise models.
Flicker noise coefficient. Reasonable values for KF are in the range 1e-19 to 1e-25 V |
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The Star-Hspice MOSFET model noise equations have a selector parameter NLEV that is used to select either the original SPICE flicker noise or an equation proposed by Gray and Meyer.
Thermal noise generation in the drain and source resistors is modeled by the two sources inrd and inrs (units amp/(Hz)
Channel thermal noise and flicker noise are modeled by the current source ind and defined by the equation:
If the model parameter NLEV is less than 3, then
The above formula is used in both saturation and linear regions, which can lead to wrong results in the linear region. For example, at VDS=0, channel thermal noise becomes zero because gm=0. This calculation is physically impossible. If NLEV model parameter is set to 3, Star-Hspice uses a different equation which is valid in both linear and saturation regions.
The two parameters AF and KF are used in the small-signal AC noise analysis to determine the equivalent flicker noise current generator connected between drain and source.
For NLEV=1 the Leff