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

[Attila Kinali]

Moin,


Thanks a lot for all the answers!


On Tue, 01 Nov 2016 09:50:38 -0500
David <davidwhess at gmail.com> wrote:

> 1. Thermocouples and temperature gradients - this is a huge problem
> and special attention will need to be directed toward the layout and
> maintaining an isothermal environment.  Careful design is required to
> get the specified drift performance out of chopper stabilized (10nV/C)
> and low drift operational amplifiers (100nV/C before trimming or
> grading).

Hmm... I guess I will have to put everything into a machined block of
aluminium or even copper/brass/bronze to keep the temperature gradients
low and temperature variations slow.


> 5. Pink Noise - 1/f noise increases as frequency decreases.  Chopper
> amplifiers have flat 1/f noise so are invaluable below about 1 Hz.

I was thinking about using low noise opamps (probably LT1128 or LT1677)
with offset compensation using a LT2057 on each of them. This
should at least kill the 1/f noise and I would guess also most of
the opamp induced temperature variation. Does that make sense?
Or should I skip the low noise opamp and use the LT2057 directly
with some second order LP filter with 100Hz-1kHz bandwidth?

			Attila Kinali

-- 
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