• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 50 subscribers
  • Views 208 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.

INA2180: Unused CSMs: floating or GNDed?

David F. Chan
Expert 5350 points
Part Number: INA2180

Hi Team,

For current shunt monitors like the INA2180, if one of the channels were not used for some reason, should the unused amp be left floating, GND'ed, or shoudl it be configured differently?

  • 0
    Guru 140200 points

    Hi David,

    connecting both inputs of the unused channel with shortest connections to the ground pin of INA2180 is a good idea. Let the associated output pin float, though.

    Kai

  • 0 in reply to kai klaas69
    TI__Mastermind 26485 points

    Hello David,

    I agree with Kai.  If you need them to be available place some shorting resistors to GND and a node you can connect to another node at a future time.  Then all you need to do is remove shorting resistors.

  • 0 in reply to Javier Contreras4
    TI__Expert 5350 points

    Hi Kai and Javier,

    Thanks, appreciate it. Somewhat related question, in the case when the INA2180 is not supplied power, but IN+ and IN- are around 10V, the output of the current sense amp would still be limited by Vs at 0V, correct? Or will the output gradually rise to ~10V?

  • 0 in reply to David F. Chan
    TI__Mastermind 26485 points

    Hello David,

    With the power not available the output does get biased through the inputs.  The output does go to about 0.6V even when the input 10V VCM and inputs shorted.  As soon as the Vs goes to an operating point it returns to the correct output.

    When VS = 0V the output is not enabled so the drive is very limited as it is not a normal operation.  With a 10kΩ load to GND we were able to drop it down to 0.2V.  I assume as you increase the load you can drop the voltage even further.