I mean if the 2nd stage is free....
Another use I realized was IF there is no gain in the input buffer, you can parallel the opamps stages to lower noise at the input. You just have to add a very small series R (1 - 100r) passive summer called ballast resistors.
You can see the difference of...
Was talking to a peer about this the other day.
The buffer ofc reduces the output impedance of the midpoint much closer to 0, which trends towards an ideal voltage source.
You have to be careful though bc the opamps contributes its own self- noise.
So LMK if I'm re-hashing here but the leakage is the failure of the diode to act as an open circuit when "off" ?
AND
The series resistance is the failure to act like a short when it is on?
I would think Vf is easily worked around by scaling input amplitude into the diode circuit.
I was gonna say just that about DC, I know there is concern about supply noise on DC traces however I'm fairly convinced in most circumstances that is well enough filtered to be a non issue.
I'm sure in your world voltage clearance is the bigger concern.
I have been turning my attention in layout to fighting instability.
I've read the bulk of routine talking points about tight NFB routing, impedance scaling, separating GND planes (divisive in modern day), star grounding etc etc.
The question I have is have you found empirically a general rule...