Difference between Active filters?

[cupoftea]

Hi,
At a recent interview, i was shown a page with three opammp based active filters on it.
They were all slightly different in configuration.
Two had one opamp, the other had two opamps.
They told me that the roll-off, gain and cut-off frequency, bandwidth, etc was the same for each filter.

They then asked me what the difference was between them.

Do you believe they were referring to some having more Johnson and shott noise etc?

 

[danadakk]

Could be :

1) Input Z
2) Output Z
3) Noise as you pointed out
4) Component sensitivity analysis, affects of component changes
on H(s). https://www.ti.com/lit/ml/sprp524/sprp524.pdf
5) Power consumption

To name a few


Regards, Dana.