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ADS127L01: ADS127L01 - REXT resistor value

MIKHAIL SALOV
Expert 5285 points
Part Number: ADS127L01

Good day Colleagues,

According to the datasheet REXT resistor has to be 60,4kOhm +/-1% (for HR or LP mode). Is there a reason for that why it has to be so precise?

What happens if the resistor deviates from that value? For example, if resistor value is 64,4kOhm instead of 60,4kOhm

Could you also give some recommendations about the REXT resistor value?

Thank you, Mikhail

  • +1
    TI__Mastermind 36170 points

    Hello Mikhail,

    The REXT resistor sets the values of internal bias currents, which can effect settling time resulting in slightly higher noise.

    The device will work with REXT=64.4kOhm, but may not meet datasheet specifications over all operating conditions.  We fully tested and characterized the ADS127L01 at 60.4kOhm for the HR and LP modes, and provide some tolerance of the resistor to meet all specifications.

    I recommend the customer use 60.4kOhm, +/-1%, in order to operate under the proper conditions that the part has been tested and specified.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    TI__Expert 5285 points

    Thank you very much,

    Mikhail