Input offset voltage/bias current noise contribution in operational amplifiers
In noise analysis of operational amplifiers, the following is considered:
- Noise generated by the external components (resistors in feedback network etc.)
- Noise generated by the operational amplifier itself
Manufacturers provide "input-referred" voltage and current noise specifications for most operational amplifiers. This figure includes shot, thermal, and flicker noise (Texas Instruments). Op-amps also have an input offset voltage and input bias current specifications.
Does the input offset/bias current contribute to the noise of the operational amplifier? If yes, is it included in the input-referred noise figures or does it have to be accounted for separately?