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Question about AD8495

Hi All,

I have a question about the AD8495. Please take a look at the attachment.

I think it is not out of spec, but I would like to know the cause of these variation.

Regards,

Kazu

QuestionaboutAD8495.pdf
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  • Hi Kazu,

    Yes, that equation is used to correct the nonlinearity and implementing it within the software will get the error down to +/-1.5mV, or less than +/-0.5degC over the 0 to 220degC temp range.   

    To get this equation, we took the data from the NIST thermocouple table, calculated the expected output voltage of the AD8495 for each temperature over the 0 to 220degC range, and took a 6th order polynomial fit of the data.  The fit is not perfect, so there will be some error between the calculated output voltage from the equation and the output voltage from the table - in this case it is +/-1.5mV.  

    Regards,

    Jordyn

Reply
  • Hi Kazu,

    Yes, that equation is used to correct the nonlinearity and implementing it within the software will get the error down to +/-1.5mV, or less than +/-0.5degC over the 0 to 220degC temp range.   

    To get this equation, we took the data from the NIST thermocouple table, calculated the expected output voltage of the AD8495 for each temperature over the 0 to 220degC range, and took a 6th order polynomial fit of the data.  The fit is not perfect, so there will be some error between the calculated output voltage from the equation and the output voltage from the table - in this case it is +/-1.5mV.  

    Regards,

    Jordyn

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