INA125: Maximum Ratings V_Ref out

Fabian Hoppe

Part Number: INA125
Other Parts Discussed in Thread: INA818, INA188

Hi,

i couldn't find maximum ratings in the datasheet of the current for the V_Ref_Out pin in order to calculate the minimum resistance

of the Wheatstone bridge for a load cell application. Can anybody tell me where I can find them?

over 4 years ago

0 Tamara M Alani over 4 years ago

TI__Genius 10850 points

Hi Fabian,

Thank you for your post, I can help you.

On page 2 of the datasheet, you can see that the Voltage Reference is specified for a range of 0-5mA. You want to make sure your bridge resistor values are not drawing more than 5mA.

This could mean that 2.5V excitation voltage with a 350ohm bridge can draw: 2.5V/350ohm = 7.1mA. This too much current and may short circuit some internal circuitry.

-Tamara

0 Fabian Hoppe over 4 years ago in reply to Tamara M Alani

Intellectual 360 points

Thanks for the fast answer. So its actually not very suitable for strain gagues and bridges. Is there any good alternative?

Best regards

Fabian

0 Tamara M Alani over 4 years ago in reply to Fabian Hoppe

TI__Genius 10850 points

Hi Fabian,

We don't have any other instrumentation amplifier with the same internal voltage reference as the INA125. However, take a look at our INA818. This is our new high-precision instrumentation amplifier suitable for many precision applications, including strain gauge measurements.

Here is the INA818 datasheet: http://www.ti.com/lit/ds/symlink/ina818.pdf

Another option is the INA188, this is a zero-drift instrumentation amplifier designed for weigh scales. Here is the INA188 datasheet: http://www.ti.com/lit/ds/symlink/ina188.pdf

-Tamara

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INA125: Maximum Ratings V_Ref out