Black box modelling of the Op-Amp including switching power supply on effect

In general, models at the device and circuit levels are very important in system design. Building compact models at the circuit level is complicated, needs a lot of physical information about the circuit and moreover it has a long simulation time. We present in this paper an alternative modeling methodology, black box modeling. In this technique, we need only the output behavior of the circuit. We get this behavior either from measurements or simulations from previously built compact models. We apply this technique to the operational amplifier as a case study. We use the Op-Amp, BSIM3v3-based compact transistor model, to obtain the performance of the circuit. An excellent agreement is obtained between the output voltage from the black box model of the Op-Amp (for both of the effect of the switching power supply on and the steady state behavior) and the corresponding output from the model used to build it.