Noise

The noise model comprises two body components, a thermal (white) noise component and a flicker (1/f ) noise component, thermal noise components for each contact resistance, and short noise components for each parasitic diode. These components are noise current spectral density (in A2/Hz ) that are implemented as a noise current sources in parallel with the associated element.

The thermal noise component of the resistor body is based on its DC conductance,    

(-36)

where k     is Boltzmann’s constant,     TK     is the device temperature (in Kelvin, including the effect of self-heating), and         Geff     is     the effective     conductance     of     the resistor (at the temperature T ). Similarly the thermal noise of each end         resistances is    

(-37)

The flicker noise component is DC current dependent and scales with geometry per the physical restrictions mentioned earlier.

(-38)

where     f     is frequency (in     Hz ), afn and bfn are model parameters, KFN(T ) is the temperature dependent flicker noise     coefficient, I21 is the DC current in the resistor body,  and W and L are the resistor width and length respectively, in units micron (µm). If the switch  parameter for flicker noise geometry calculation sw_fngeo is 0     (false) then W and     L are design geometries, w_um and l_um respectively, else if it is 1 (true) then W and L are effective geometries, weff_um and leff_um respectively.    

The shot noise components are    

(-39)

for each parasitic diode, where Idiode is the current in the diode.