Modeling of the small-signal dynamic behavior of the TL081H

Exercise

Download the data sheet of the TL081H and design an equaivalent circuit for this operational amplifier that models the following aspects of its small-signal dynamic behavior over a frequency range from DC to 10MHz:

1. The voltage gain

2. The differential-mode input impedance

3. The common-mode input impedance

4. The output impedance

Solution

Definition of the differential-mode input impedance

Definition of the common-mode input impedance

Specification of the DC voltage gain and the differential-mode and common-mode input impedance of the TL081H

Definition of the differential-mode input voltage gain

Bode plots of the voltage gain of the TL081H

Definition of the output impedance

Magnitude plot of the output impedance of the TL081H

Small-signal model of a “voltage feedback” operational amplifier