Does anyone have suggestions for an over voltage protection circuit? I have a signal that slews very fast, where a comparator will not be quick enough to react. The only ideas I could come up with were a clamp structure or a series MOSFET with the gate biased to saturate the signal but that impacts performance since the device has a lot of variability. ESD won’t work for this application and it cannot draw any current from the signal as it is high impedance.
Electronics design has to do with voltage, currents and their calculation.
But there is not a single value in your post.
So without knowing
* about the typical (wanted) signal range..
* about the "overvoltage range"
* impedances
* energies
* application goals, like maximum distortion ..
it's only wild guessing, and time consuming