Prediction of RF interference in operational amplifiers by a new analytical model

The effect of radiofrequency interference (RFI) in MOS and BJT operational amplifiers (op-amps) is dealt with; in order to obtain analytical expressions which can be useful for design purposes, a second order circuit analysis has been performed. This approach grants a good insight in the nonlinear mechanisms involved in the RFI induced DC offset shift in opamps and relates this behavior to design parameters and parasitics. The validity of the proposed model is discussed comparing theoretical prediction and computer simulation results.