Differential Amplifier- minimum detectable input

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JeremyB

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Hi guys,

I'm looking for a diff amp that can detect the difference of 1uV across it's +/- inputs. The problem is that I'm not very familiar with diff amp specs so I'm not sure what to look for exactly. Help would be greatly appreciated.

Application: ac current sensing


Thanks,
Jeremy
 

Try to search for " low noise instrumentation amplifier". You do not say what bandwidth you require or even if its AC or DC. What do you mean by "detecting" - driving a meter? actuating a loudspeaker?. . .
Frank
 

Amplifier noise and offset voltage are the limiting factors. Offset voltage matters in case you want to sense DC voltage. Amplifier noise can be as low as µV for MHz bandwidth down to nV for Hz bandwidth.
 

Hello

to detect 1uV input voltage change will need very high gain circuit which doesn't have any offset voltage, for this case it is hard even to use CMOS Differential amplifier which exhibit an input offset voltage, any way by the meaning of very high voltage gain you can not use simple differential amplifier rather thanhigh performance op-amp.

it seem from your question that you are just interest in the detection value, mean you are looking to work if I am not wrong with open loop condition, if it is right then you have to search for comparator design circuit which has a slight different from general Op-amp specially if you take the transient response in your consideration
 

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