I love the specs on the OP275, and plan to make extensive use of it in my designs.
I am a little unsure of how to approach loading, which the data sheet mentions to be aware of. It seems to hint at a degradation in performance concerning high source impedances, both ingoing and outgoing, not just as a result of thermal noise. I believe in an Walter Jung application note this distortion however, is mentioned as not being exclusive to the OP275 and most opamps suffer, to some extent.
The circuit I am working on at the moment, is an offset removal servo design using aspects of figure 6-16 in Chapter 6 of Opamp Applications. This uses high (1Meg) resistors to set 2 filter coefficients at DC level. In this situation might I approach the limits of what the OP275 is capable of driving? Am I reading between the lines wrongly, or perhaps being overcautious?
Many thanks for any input.