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floating or grounded AINCOM for differential input

Dear,

I am using ASD1256 for loadcell signal reading. Input is differential. My current  layout has AINCOM connected to the ground. 

My question is -  what is the best practice for the bet performance? Should that AINCOM pin be connected to the ground or floating for differential measurements?

  • Hi user4847416,

    welcome to our forum. It seems like we somehow missed your question in the forum. I do apologize that we didn't respond to you earlier. We usually strive to respond within 24 hours.

    For best performance, we recommend to leave unused analog inputs floating or to connect them to a voltage somewhere around mid-supply - this includes the AINCOM pin as well.
    The 2nd best option is to connect them to AVDD. The least preferred option is to connect them to AGND.

    However the difference in performance will be very minor.
    The connection of unused analog input pins affects the input bias currents on the analog inputs that are selected for the measurement. But we are talking differences in the sub-nA range here only.

    Regards,