Hi,
Currently I am involved in quite challenging AFE design for myography sensor application.
One of the impotrant issues for SNR improvement is filtering stages noise.
For example here is useful article explained the influence of high Q stages to overall output noise
https://e2e.ti.com/blogs_/archives/b/precisionhub/posts/noise-from-active-filters-an-unwelcome-surpriseWhen I have tried to simulate the noise behaviour of LPF by means of LTspice, actually the lower Q section produces less output noise,
But I was a little bit confused that noise performance doesn't depend obviously on OpAmp type even if noise simulation is mentioned in Spice lib description.
For example, below are two sets of simulation results, first for more noisy (according to datasheet) TLV9042 Opamp and second set for much less noise MAX44260 Opamp. In both cases resistors and caps are ideal ones, so only Opamp noise should affect the final result.
But plots show that MAX44260 has more output noise, which is unexpected literally.
Is it simulation bug or incorrect LTspice work with third-party spice models?
Hope that in real life noise performance depends on Opamp type ans less noisy opamp will produce the less total output noise.