The Instrumentation Amplifier ICs amplify the difference between two input signal voltages, while rejecting any signals that are common to both inputs. The DC precision and gain accuracy is maintained within a noisy environment, and also where large common-mode signals (AC power line frequency) are present.

Instrumentation Amplifiers, Texas Instruments

Instrumentation amplifiers are composite differential amplifier blocks generally incorporating a classic three operational amplifier configuration. They provide high input impedance, very high common-mode rejection and allow differential gain to be accurately set via internal or external resistors. Differential amplifiers offer low DC offset and drift coupled with high open loop gain and low noise and are frequently used in high-precision test and measurement applications and electrically noisy environments.