Improvement of the Gain Accuracy of the Instrumentation Amplifier Using a Very High Gain Operational Amplifier

This paper evaluates the performance of three operational amplifier (Op-Amp) based instrumentation amplifier (INA) topology using two variants of Op-Amp - one with a very high gain with respect to the other Op-Amp topology. The gain accuracy and common mode rejection ratio (CMRR) of the INA is improved with the use of the very high gain Op-Amp designed using a folded cascode amplifier. The CMRR of the INA using folded cascade Op-Amp is 114 dB which is 43 dB higher to that of INA using differential amplifier.