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ADS131M08: Input impedance

Ralf Bartling
Expert 1155 points

Part Number: ADS131M08

Hello,
I have a question regarding the input impedance of the ADS131M08. In order to utilize the whole measurement range we use the ADS with a PGA=1 configuration an a divider resistor of 6.2kOhm. 
In this configuration the input impedance influences our measurement result, because the input impedance is typically 330kOhm. For this reason we want to calibrate our measurement circuit during production.

Is the input impedance of the ADS131M08 nearly constant over temperature and aging?

Are there other effects which changes the input impedance during operation?


Best regards

Ralf

  • +1
    TI__Mastermind 47355 points

    Hi Ralf,

    The input impedance is related to the gain setting and mode as you can see the plot in ADS131M08 datasheet below, it is also changing over temperature. If this is a concern in your design, ADS131E08 can be a good option for you since it has a high input impedance.

    BR,

    Dale