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INA212: Minimum Sense voltage for INA212

Rejeesh Raj
Intellectual 330 points
Part Number: INA212


Hi,
We wish to use the part INA212 in 3.3V supply rails, please specify this is viable?

In the data sheet maximum positive output voltage is specified as "(V+)–0.2".
So in our design we are expecting output swing maximum around 3.1V (As it is running on 3.3v rail).
The gain is 1000V/V for INA212, so in the above case we need input of around 3mV to get maximum output swing.
please let me know the minimum sense voltage the device will identify / starts to amplify?

If my output got saturated and the condition maintained for prolonged period, confirm the device will not be affected
Thanks
Rejeesh S Raj

  • 0
    Guru 140200 points
    Hi Rejeesh,

    there's no minimum sense voltage to make the INA212 start to amplifiy. But your sense voltage should be larger than the input offset voltage in order to keep the error minimal.

    Saturation of output does not harm, provided you do not violate the absolute maximum ratings of chip.

    Kai
  • 0 in reply to kai klaas69
    TI__Mastermind 26335 points

    Hello Rajeesh,

    Thanks for considering TI in your design.  What Kai said is correct, the device will amplify any voltage differential across your shunt.  Also as he noted, the Vos will contribute a large error for lower current measurements.  However, we also would recommend that your minimum measured current be 10x  the input bias current max (35uA) to avoid large errors.  The error contribution from input bias current can be calculated according to the equation below.  There are still yet other errors to consider, but these errors are typically smaller.

    As for saturating the output, that will not destroy the part as long as the device operates within the absolute max ratings.