Effect of conducted EMI on the DC performance of operational amplifiers

Electromagnetic interference can affect the performance of operational amplifiers even when the frequency is well above the usable frequency range of the amplifier. This can result in an apparent change in offset voltage. This effect is investigated experimentally with a number of device types. An attempt was made to compare the DC performance of various operational amplifiers in the presence of conducted impulsive EMI, as might be experienced in mixed analogue and digital circuitry. This Letter describes the test procedure and notes the results obtained.