Design of an Operational Amplifier Input Stage Immune to EMI

This paper presents a new analytical model to predict upsets, which are induced by electromagnetic interferences (EMI) in CMOS operational amplifiers (opamps). In particular, it is pointed out that the demodulation of EMI, which is experienced in feedback CMOS opamps, is related to the power spectral density of the interfering signals reaching the opamp input terminals. Furthermore, the new model is employed to design a differential stage immune to EMI.