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In a circuit I use AD8220 for measuring the sensor resistance between 100k ohm to 200k ohm. The problem is that I only get a good linearity from 100k to 110k at the output. Over 120k the output saturates.

How can I solve the circuit so a can get an linear output for 100k to 200k?


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  • Hi  

    Thank you for reaching out and sharing your inquiry.

    To be able to recommend the correct recommendation, I would like to know the different design requirements of your application.

    Isolating other components that may affect the AD8220 performance, Please cut the connection from Pin7  to (10uF cap and 10Kohm res) and confirm if this is correct.

    • What is your Sensor (s1) and intended applications?
    • Basing from your application circuit, AD8220 is using a single operation; +Vs =5V and -Vs =0V?
      • Vref (pin6) = 2.5V if variable resistor is 0ohms? If var res is 100K then, Vref = 2.62V?
    • Intended Gain =1??
    • If S1 (Sens) = 100Kohms, what is the value for +In (Pin4), is this 2.5V?
    • If S1 (Sens) = 200Kohms, what is the value for +In (Pin4), is this 3.33?

     Thanks and Best Regards,

  • Please let us know if you can provide these details being requested on your end. For the team to understand your inquiry further and be able recommend the suitable answers.

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