Validity Of The Flat Band Perturbation Technique In Non-Ohmic Region

The flat band perturbation technique (Ghibaudo, 1987) has been used extensively for the last 15 years to study and model low frequency noise in the MOS transistor. The method has `proven´ to be valid even in non-ohmic region (with a non zero drain to source voltage). In this work we show that this methodology is valid only in the ohmic region (drain to source voltage tending to zero) and establish it´s link with the Langevin method, the most fundamental noise calculation methodology