Design Techniques for Precision Amplifiers

Precision or instrumentation amplifiers are the integral part of several measurement system, and usually determine the accuracy and precision of the whole system. In CMOS amplifiers, the input-referred offset is in several millivolts before applying any offset reduction technique. Similarly, flicker noise is dominate at low-frequency often buying a sensor signal amplitude . For useful signal readout these amplifier non-idealities i.e. offset and flicker noise must be significantly suppressed. In this talk, we shall go through the evolution of instrumentation amplifier from 1970s till current age. We shall start with static offset cancellation methods and they study the dynamic offset cancellation techniques such as auto-zeroing, correlated double sampling and chopping. However, these techniques also cause some drawbacks such as noise folding, lowering input impedance, gain nonlinearity, distortion etc., which should be addressed property. several examples of reported precision amplifiers dealing with aforementioned non-idealities will be discussed in detail.