Using a high DCR inductor instead of resistor in LED/Zener voltage reference?

Question

I need a very simple, low noise Zener or LED voltage reference that will be fed by a potentially noisy (RF) voltage source.

Focusing on low noise, I was thinking of adding an LC filter before or after the reference to provide better RF filtering.

I also considered the possibility of using a high resistance series inductor in place of the equivalent resistor. Any idea how this might behave?

One advantage I see is that high DCR inductors have much higher inductance for lower cost and size compared to low DCR ones, and resistance is needed for LED/Zener current limiting anyway.

Answer 1

The idea has some sense, however you should check the values… Most of the time you need a comparatively big resistor for a zener than the DCR of an inductor (unless you are winding chromel, I guess:D)

Also be wary of parasitic winding capacitance and core behaviour, at RF they could nullify or worse your filtering intent. So depending on your frequency and signal you could end needing to wind a huge air cored inductor.

That wouldn't surprise me. The main inductor in a LISN (which is essentially part of an instrument-grade filter) I have is something like 80mm and 250mm long (and has damping resistors soldered between turns)