Check the datasheet for the OPA 2846:
Vn=1.2nV/sqrtHz, In=2.8pA/sqrtHz
that means the OSI (optimum source impedance) is 428 ohms.
The 100k resistors in the non-inverting inputs alone introduce
88uV (@100kHz BW)
What is the transducer's impedance?
?
Let me say why am looking for new design..
We are currently using the receiver module which has three
stages:
1. Trans Impedance stage
2. High Pass filter (HPF) stage
3. Unity gain amplifier (just for inverting the output of
the HPF)
Well...we used LM2662 as a -5V supply..
Here on we could see the hell noise below 100kHz..
I couldn't get rid of this noise by using bypass caps..but
I could just reduced it..
Yet there is a lot of noise all across the circuit ranging
from few kHz to hundreds of MHz...
are the links where I have uploaded couple of documents..
I really don't know what sort of noise it is and from
where it is coming...
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L'absence de virus dans ce courrier ¨¦lectronique a ¨¦t¨¦ v¨¦rifi¨¦e par le logiciel antivirus Avast.
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