• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 50 subscribers
  • Views 140 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

INA226: current monitor solution for 3µA - 2.5mA

Stefan Lintner
Expert 4255 points
Part Number: INA226
Other Parts Discussed in Thread: INA238, INA228

HI Team,

a customer is looking for a current monitor solution in the range of 3µA - 2.5mA.

The supply voltage is 3.3V, SPI and I2C can be used and the solution should have an accuracy better than 10% in the range 2-20µA.

Will INA226 work here or can you recommend a more suitable solution?

BR,
Stefan

  • 0
    Guru 140200 points

    Hi Stefan,

    what shunt does the customer intend to use?

    Kai

  • 0 in reply to kai klaas69
    TI__Expert 4255 points

    Hi Kai,

    customer was considering a 30 Ohm resistor.

    At 2.5mA maximum current this would give 75mV drop, which would still be below the max input voltage of the INA226.
    At 2µA the shunt voltage would still be 60µV.

    BR,
    Stefan

  • 0 in reply to Stefan Lintner
    TI__Genius 17990 points

    Hello Stefan,

    In general, the INA226 may be hard to use at such low current values because the input bias current of the device has a typical value of 10µA, which is higher than what you are trying to measure...  If you want a device with comparable accuracy and price but with lower IB, then you would want to switch to the INA238, which has a typical IB of 0.1nA. 

    If you decide you want more accuracy, then you can switch to the INA228, which is the best device we have for this situation.