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Noise of analog switch ICs
ricko_uk:
Hi,
I have two coils at the bottom of an AC-excited Wheatstone bridge and the variation/measurement between those points (classic Wheatstone bridge measurement) is only uV.
So they are fed into an instrumentation amplifier. The application is clearly very low noise.
I am considering multiplexing various Wheatstone bridges into a single Instrumentation Amplifier through analog multiplexers/switches. But I cannot find details of the noise contribution of such switches.
Does anybody have any information about this? Any info much appreciated! :)
Thank you
moffy:
I would think crosstalk would be more of the issue, but if you lower the input impedance they feed into it can be reduced. The article: https://www.analog.com/media/en/training-seminars/tutorials/MT-088.pdf talks about switch basics.
OwO:
Usually negligible and is determined by the insertion loss of the switch. I recommend using RF switches instead of analog switches because they will have far lower parasitics. I've tested the MXD8641 and MXD8625C to work down to DC and can pass -1.5V to +1.5V.
SilverSolder:
--- Quote from: OwO on February 02, 2020, 04:55:07 am ---Usually negligible and is determined by the insertion loss of the switch. I recommend using RF switches instead of analog switches because they will have far lower parasitics. I've tested the MXD8641 and MXD8625C to work down to DC and can pass -1.5V to +1.5V.
--- End quote ---
Looks like an interesting part.
Did you check charge injection and other misbehaviours, just out of interest?
ricko_uk:
Thank you all for the feedback! :)
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