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Input Impedance in Differential Mode

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Hello everyone,

When I bought the USB 6212 card, I was impressed with the high input impedance stated for it - 10 GOhm.

In the specification, this is stated to be for between AI+ and AIGND.

So what is the input impedance under differential connection?

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Accepted by topic author navneet

Hi Navneet,

 

The question you have posted is actually a Multifunction DAQ question. You should post these questions in Multifunction DAQ Forums. You would get much faster responses to questions that are posted in the correct forums. 

 

The input impedance, in differential mode is a little less then twice the impedance of AI referenced to ground. What this means is that it will be ~20 to 19 GOhms. The actual value is not available because it is such a high input impedance.

 

Best Regards,

Jignesh

Best Regards,
Jignesh Patel
Senior RF Systems Engineer
CLD
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Hi Jignesh,

Thanks for your reply. I was waiting for someone to answer that. And thanks for the advice.

One thing Jignesh, is there any document I can reference to state wht you have stated? want to put that in my thesis 🙂

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Hi Navneet,

 

The information you asked for is not stated specifically in any documentation. I know this information because I am an Applications Engineer with National Instruments.

 

Best Regards,

Jignesh P

Applications Engineer

Best Regards,
Jignesh Patel
Senior RF Systems Engineer
CLD
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Thanks Jignesh,

Will move ahead with this. 

The input impedance in differential mode is much higher then what my application requires. Gives me much confidence.

Thanks again :).

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