6.7 OFFSET MODEL FOR AN OPERATIONAL AMPLIFIER
We had neglected the offsets that are invariably present in any Practical Opamp (POA) circuit until now. We take up the analysis of offset performance of Opamp circuits in this section and develop a model to account for offsets in Opamps.
Consider the circuit in Fig. 6.7-1(a).
The output is usually at the saturation level when both the input terminals of a POA are shorted to ground. However, it is not possible to predict whether the output is at a positive saturation level (V sat) or at a negative saturation level (–V sat). An experiment will be required to find that. Two Opamps of the same type; for instance 2 μA741 ICs, need not show the same saturation level under the input-shorted condition.