• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 47 subscribers
  • Views 109 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

INA181: Input Common Mode Abs Max Clarification

TI_Lover
Prodigy 160 points
Part Number: INA181

Tool/software:

Hello TI Team :-)

The basic definition of input common mode is the average voltage of IN+ and IN-.

Does this always hold true? Especially when reading the Abs Max table?

For example:

  • IN+ = 0.0V
  • IN- = -0.4V
  • Input common mode = -0.2V

Is this scenario safe, because input common mode is within the acceptable range? Or not safe because IN- exceeds the abs max value of -0.3V?

Thank you!

RB

  • +1
    TI__Genius 17070 points

    Hello RB, 

    Thank you for your post. 

    For amplifiers in general, yes, your definition is correct. However, for CSAs, we spec the datasheet for each input independently. 

    So the common mode limitations apply to both pins. 

    For your example above, the common mode voltage would be evaluated separately where IN+ has a 0V common mode and IN- has a -400mV common mode voltage (violating the datasheet). 

    Best Regards, 

    Joe