INA128, 129/ TINA-TI

Kuramochi Tadahiko

Guru 28715 points

Hi,

My customer confirms operation of INA128U and INA129U by Tna-TI Ver.9.3.50.40.SF-TI.

The power supply is ±5V, the input voltage ±3.766V by voltage divider.

However the results are a little low, are each +3.577234V and -3.635149V.

When power supply is ±15V, the results are normal, anre each +3.766148V and -3.766263.

What is affected this result?

Please refer attached file.

INA128 TINATI.zip

Best Regards,

Kuramochi

over 7 years ago

0 John Miller - Sensing over 7 years ago

TI__Mastermind 33240 points

Kuramochi,

I believe that with +5V/-5V the output is getting too close to the power supply rails.

The data sheet says the output can be as close as 0.9V to the power supplies (typical) and 1.4V minimum.
So with the 5V supplies, the output is starting to compress in a way that is compatible with the data sheet.

If the power supplies are increased from +5V/-5V to +6V/-6V, the output becomes the same as for +15V/-15V supplies.

I hope this helps. Please let me know if you have any more questions.

Regards,
John

0 Kuramochi Tadahiko over 7 years ago in reply to John Miller - Sensing

Guru 28715 points

John-san,

Thank you for your reply.
Does it mean that the offset voltage is depending on power supply?

Best Regards,
Kuramochi

0 John Miller - Sensing over 7 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 33240 points

Kuramochi,

The model's power supplies do not very much with the power supplies.

I swept the power supplies from +-5V to +-15V and the output offset varied only by 1uV.

I don't know the behavior of the real part. it should be given in the data sheet.

Regards,
John

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INA128, 129/ TINA-TI