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INA129: Gain drift

Kenji Ohno1
Genius 5095 points
Part Number: INA129

Hi Team,

I have a question about Electrical Characteristics “Gain vs temperature”.

・ 50-kΩ (or 49.4-kΩ) With the resistance being typ. ± 25 ppm and max. ± 100 ppm, is G = 1 + 49.4 kΩ / Rg, so is it the value when G = 2?

・ Is "Specified by wafer test" a test with tip shape?

・ I would like to know the Gain Drift value when Gain = 10.

　Can you tell me the ability value data? (Temperature range: -10 to 85℃)

Best Regards,

Kenji

  • 0
    TI__Guru 64140 points

    Let me first say, that in INA129 datasheet gain equation, G = 1 + 49.4 kΩ / Rg, the initial gain error and drift specifications assume Rg value to have no error (@25C) and no drift.  Thus, the only consideration is given to INA129 internal gain error and drift.  Therefore, any error related to the external Rg must be additionally included in your worst case error calculation.

    Assuming Rg has no drift, the maxiumum gain drift for G=2 or G=10 would be: Max Gain_drift = (10^2 + 100^2)^0.5 = 100.5ppm/C (two uncorrelated quantities)

    Specified by wafer test means INA129 is tested and its resistors are trimmed with a laser at the wafer level.  I do not know what you mean by ability value data.