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TMAG5273: MAX Sensitivity Error

Christopher Fathallah
Prodigy 10 points
Part Number: TMAG5273

Tool/software:

I am trying to use two of these hall-effect sensors to distinguish a few different magnetic states, but I'm concerned with the accuracy of the sensor.

I am struggling to understand what the sensitivity error is referring to. Is it a percentage error from the true magnetic reading? For example, if I read a value of 60 mT and since the maximum sensitivity error is ±20%, the value read could be between 48 and 72 mT.

That's a very large range, and makes it difficult to distinguish between magnets. Is this how the sensitivity error should be interpreted, assuming all other sources of error are ignored?

  • 0
    TI__Mastermind 26335 points

    Hello Christopher,

    Thanks for considering to use Texas Instruments.  Your understanding of the specification is correct +-20% error would mean a 60mT value could be measured as a value between 48 and 72mT.  However, that is not what you might typically expect from that device.  The max bounds are more conservative than the worst case we measure in our validation phase.

    If the risk of a 20% error is too high, you might consider the TMAG5173, which has a max sensitivity error of 3.3% at 25C.

  • 0 in reply to Patrick Simmons
    Prodigy 10 points

    Thanks for the reply Patrick!

    Is the TMAG5173 designed to be a drop-in replacement to the TMAG5273?

    Just to understand a bit more about this ±20% sensitivity error, is this something that can be calibrated for? Or can it not be controlled through calibration? We're thinking to run it through a calibration process at the factory to remove any biases, but this might only remove B_off. Is this correct?

  • 0 in reply to Christopher Fathallah
    TI__Mastermind 26335 points

    Hello Christopher,

    Yes, the TMAG5173 is a higher performing version of the TMAG5273.  Package and pinout are the same.

    I think you could potentially calibrate the error out at the factory if you are able to generate a repeatable controlled field of a known value (a value near 80% the typical max might be reasonable), to characterize the sensitivity for an individual device.    Based on that measurement you could scale the measured value.  For your controlled field, you could use a Helmholtz coil or possibly a magnet with spacer such that is designed to place the magnet the same relative distance for each measurement.