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Need help with fully differential amplifier

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doncarlosalbatros

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Hello,

I have a uni polar balanced/differential output transducer where wiring can be seen at page 41 of this manual.

The transducer outputs around +/-200mV and I want to amplify this with a gain of at least 10. The data acquisition board is also differential inputs. And I want this to be differential because of better noise rejection.

Now I want to amplify the transducer signal and obtain differential signal at the output with gain of at least 10.

I found this differential amplifier, but it seems it is not fully differential. But it is great that it has inner gain so no gain temperature issues. But its output is single ended I guess (?)

My problem is I want a fully differential amplifier in DIP package which can work any dual supply voltage between min +/-5V up to max +/-15V.

But I couldn't find a single one in the market. Does anybody have experience with that? My frequency of interest in this force transducer application is from DC to 150Hz.

The best would be of course fixed gain fully differential amplifier in DIP package, otherwise resistive networks(which are also not DIP) to eliminate temperature effects on gain or CMRR needed.


(How about using a single ended to differential ended driver after this INA106. My problem is I'm restricted with supply rails and DIP package+)
 
Last edited:

doncarlosalbatros said:
Hello,

I have a uni polar balanced/differential output transducer where wiring can be seen at page 41 of this manual.

The transducer outputs around +/-200mV and I want to amplify this with a gain of at least 10. The data acquisition board is also differential inputs. And I want this to be differential because of better noise rejection.

Now I want to amplify the transducer signal and obtain differential signal at the output with gain of at least 10.

I found this differential amplifier, but it seems it is not fully differential. But it is great that it has inner gain so no gain temperature issues. But its output is single ended I guess (?)

My problem is I want a fully differential amplifier in DIP package which can work any dual supply voltage between min +/-5V up to max +/-15V.

But I couldn't find a single one in the market. Does anybody have experience with that? My frequency of interest in this force transducer application is from DC to 150Hz.

The best would be of course fixed gain fully differential amplifier in DIP package, otherwise resistive networks(which are also not DIP) to eliminate temperature effects on gain or CMRR needed.


(How about using a single ended to differential ended driver after this INA106. My problem is I'm restricted with supply rails and DIP package+)
Click to expand...

Your DIP requirement seems kind of arbitrary. Can you explain why that’s a requirement?
 

Connecting opamps as differential amplifiers externaly will not match that of of an ina.

one option is to use ad620 ina as you have only one resistor to set the gain and others are internally laser trimmed for precision.

and ad620 is single ended output but differential input.(for connection to your sensor).

But you can connect the o/p Reference to DAQ REfernce in for better noise rejection in o/p side.
AD620 boards are available readymade so not much work on connections (search amazon and other online sites ...)
 

With only 150 Hz bandwidth, there's absolutely no advantage in using fully differential signaling between amplifier and DAQ board. Instead you can use pseudo differential scheme, connection In- to a reference voltage near the amplifier, e.g. identical with the ref input of the instrumentation amplifier. There's also the option to use a -1 amplifier if total signal swing is critical.

So it boils down to use basic standard components.
 

FvM said:
With only 150 Hz bandwidth, there's absolutely no advantage in using fully differential signaling between amplifier and DAQ board. Instead you can use pseudo differential scheme, connection In- to a reference voltage near the amplifier, e.g. identical with the ref input of the instrumentation amplifier. There's also the option to use a -1 amplifier if total signal swing is critical.

So it boils down to use basic standard components.
Click to expand...

Hello,

There's also the option to use a -1 amplifier if total signal swing is critical.
Click to expand...

What is "a -1 amplifier" ?
 

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