Operational Amplifier
P. Heymann, Matthias Rudolph · 2021
Operational amplifiers are widely used integrated circuits with very high gain. Different transfer characteristics can be easily realized by a few passive components before the input or in the feedback circuit. The ideal operational amplifier has an infinitely large gain, an infinitely large input resistance, and an unlimited frequency range. Although the real values are of course finite, the characteristics of the operational amplifier in the circuit are almost exclusively determined by the external elements. The noise characteristics are described by a noise current source and a noise voltage source in front of the amplifier, which is thought to be noise-free. The approximation of the frequency dependence of the noise is based on the data sheet. The approximation used in the integration refers to the spectral power densities plotted on a frequency axis in logarithmic scaling.