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INA3221EVM: INA3221EVM

Part Number: INA3221EVM
Other Parts Discussed in Thread: INA3221

Hello 

I have a query regarding the board, I need to know what is the min Load current it can measure?

Regards

Akash

  • Akash,

    This is a tough question to answer for any current monitor, because it doesn't address two key issues:

    - what is your full scale range (i.e., what is the largest current you need to monitor)?

    - what level of error can you tolerate in the measurement?

    The reason the first part is pertinent is because if you needed to measure a smaller current range, the option to use a larger a shunt is present. That said, the larger the shunt, the smaller the top end of the range, and you could saturate the device before reaching the higher end of your range. The second part is more pertinent to what find acceptable error in the measurement. Do you need 1% error, or is 10% error fine at your minimum level? We publish a tool in the INA3221 product folder that allows you to examine just such conditions:

    It will allow you to populate different values of shunt resistance and range to view a RSS approximation of error you will see. 

    Finally, there are also bias current present on the input lines that will also contribute to the error here. As they are around 10uA, I would say this would limit your realistic current measurement to somewhere in the 10's of microamps, as these currents could dominate the measurement at lower levels. 

    Let me know what questions you have here.