INA821: Design review and question

Hi Clement, 

I will be reviewing this and will respond by the end of the day tomorrow. 

Best Regards, 

Chris Featherstone

Hi Chris,

Unfortunately installing Tina Ti is complicated due to our IT rules.

Thank you for checking our design, we had low fear that it wouldn't work with a pure differential input.

However, you did not answer to the second part of my question.

I also have a question, we are being asked if this would be compatible to acquire a single-ended 4V square wave, with negative input being connected to the GND.

From my understanding of the datasheet, I feel like this would be problematic as this would lead to unbalanced inputs as per requirement for Input Bias Current Return Path.

I believe from your answer regarding the balancing and the fact that we would be trying to acquire with the INA a single ended analog signal, that this wouldn't work.

Clément

Hi Clement, 

I ran the 4V square wave below. I am not sure what to look for to answer the question. The square wave is distorted due to RC time constants in the circuit but passes through fine. 

Best Regards, 

Chris Featherstone

Chris,

You didn't catch me.

In your simulation you still created a true differential signal.

What I was talking about is inputing a single-ended signal with the other signal of the front-end input connected to GND.

And as I stated I was seeking your advice but believed this won't work due to unbalance created on the input.

Clément

Hello Chris,

Thank you for your answer.

We intend to use C0G/NP0, so that's fine.

Clément