ABSTRACT
The non‐ideal Op‐Amp differs from the already analyzed ideal Op‐Amp in many features. A very accurate Op‐Amp model could be developed by replacing each amplifier transistor and diode by its respective network model. Nevertheless, a typical Op‐Amp comprises at least 20 transistors in general. By choosing the Ebers‐Moll complete model (with 13 elements) for the transistors, the resulting circuit presents around 260 elements. It is possible, however, to develop a simpler model – often called macro‐model – for the operational amplifier, which is able to accurately represent the real Op‐Amp behavior. This behavior is summarized by the following characteristics: finite input resistance, nonzero output resistance, frequency‐dependent open‐loop gain magnitude, frequency‐dependent phase shift, output voltage limitation and slew rate limit. The manufacturers of operational amplifiers usually extract and assure seven main parameters and often extract five secondary parameters of their products. To provide a basis for discussion, the definitions of these parameters follow in the next sections.
