AD620 Reference

Hi !

So I shot myself in the foot with another IA that has the same reference pin that this AD620 has. I want to operate the device from a single supply, so V- will be 0V and V+ will be 3.3V. I want to measure the voltage across a shunt resistor and amplify it. When no voltage is present I want it to output 0V and when a voltage is present it should output the measured differential voltage multiplied by the gain.

Due to this I dont want to level shift the output at all. Could I therefore connect the reference pin to 0V or rather to V-?

From the datasheet I have my doubts about this: Voltage Range −VS + 1.6 +VS − 1.6

This seems to imply the lowest voltage i would be able to supply to the reference terminal is 1.6V?

Thanks in advance for any help!

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  • Hi EngJunkie,

    Unfortunately, you will not be able to get the output strictly zero volts at single supply, even if you will use a rail-to-rail amp because output transistors has drop voltage. You can calculate the lowest output voltage using the parameter "output voltage swing" from datasheet.

    Yes, you are correct, minimum voltage at reference pin is 1.6 V in your case.

    Regards,

    Kirill

Reply
  • Hi EngJunkie,

    Unfortunately, you will not be able to get the output strictly zero volts at single supply, even if you will use a rail-to-rail amp because output transistors has drop voltage. You can calculate the lowest output voltage using the parameter "output voltage swing" from datasheet.

    Yes, you are correct, minimum voltage at reference pin is 1.6 V in your case.

    Regards,

    Kirill

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