[volt-nuts] How to keep voltage stable in the sub-100nV range?

[David]

On Wed, 2 Nov 2016 06:56:46 +0100, you wrote:

>Hello David,
>
>On 01.11.2016 15:50, David wrote:
>> avoid Mylar/polyester/PET and high dielectric constant ceramic
>> capacitors.
>
>Do you have some specific recommendations/suggestions what to use?
>
>Polypropylene? PTFE? Wet Tantalum capacitors (extreme expensive)?
>
>Thanks,
>
>Andreas

Wet tantalums might be the best for very long time constants but are
useless for settling times below hours to days.  Some low leakage
aluminum electrolytics are just as good.

Charles pretty much covered it but I am not sure that polypropylene is
always worse than polystyrene.  Some of the other plastic films are
pretty good also but polypropylene is the most common high performance
option.  Teflon is the best but is also expensive and has poor
availablity.

When I looked into this a couple months ago in connection with
building a long time constant integrator for an analog only GPSDO, the
primary limitation was insulation resistance of the capacitor.  Even
the best low dielectric constant C0G/NP0 capacitors were much worse
than polypropylene film which was itself was much better than
polyester.