Precision operational amplifier generally refers to the operational amplifier with offset voltage less than 1mV, and emphasizes that the drift value of offset voltage with temperature change should be less than 100V. For DC input signal, VOS and its temperature drift should be small enough, but for AC input signal, we must also consider the input voltage noise and input current noise of operational amplifier, which are more important in many applications. At the same time, many applications need to use programmable high-precision operational amplifier (PVGA) to dynamically adjust the amplification factor in the signal chain. The performance of precision operational amplifier is much better than that of general operational amplifier, for example, the open-loop magnification is larger, the CMRR is larger, the speed is slower, and the GBW and SR are generally smaller. Offset voltage or offset current is relatively small, temperature drift is small, noise is low, and so on.