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DRV5053: drv5053 first saturation

Part Number: DRV5053

Hello TI,

Im currently testing the DRV5053 sensor for a project, specifically the -11 mV/mT, -23 mV/mT, -45 mV/mT and the -90 mV/mT. My first question is if there is more documentation of the DRV5053 sensors, I need to collect as much info as possible. Most important things I need to know is the difference between single units and the differences between batches of sensors for example. 

My next question is regarding the tests I have performed untill now. It seems all the sensors change their output values after the first saturation, I started noticing that the values of the first test I performed were lower than the tests i did after this first saturation. So i took a new sensor and did a test without saturation and noticed the values stay the same untill I saturate the sensor again in one of the following tests. this seems to happen both for the positive and negative sensitivity. In the added graph (top left window) you can see that the runs before saturation are different than the runs after saturation (there is a noticeable shift in values). I was wondering if there is any information about why this shift in values happens. 

Thanks in advance!

Greetings,

Brian Crutzen

Junior Researcher

ACMIT Gmbh

  • Hi Brian,

    You can find more technical information at the DRV5053 website, technical documents tab.(link below).

    One of our applications engineers will get back to you to support you with your other questions. 

  • Hi Brian,

    I'm not sure I understand what you mean by "saturation". Could you please describe your test setup and procedure in more detail? Also, could you plot the two sets of data over similar x and y intervals so the differences are easier to identify?

    Best Regards,
    Harsha
  • Hello Harsha,

    Saturation means the sensor reached it's highest value (it's max value thus being saturated). the setup consists of a linear stage (motor) with a magnet attached on a peg(see image). The motor is programmed in a way that it makes small steps towards the sensor element sensor's values are measured in sequence with the movement of the motor. This allowes us to make graphs of the output voltage vs the distance. B

    But as i explained before, The sensor values becomes slightly higher after the senser already had a test in which it reached its maximum value before. so after taking the sensor out of the package (unused) i tested it once in a way so it doesnt reach the highest value(1st run curve). And after this I did a test in which i increase the distance so that the sensor does reach the highest value(2nd run curve). After I did this test the values would be slightly higher for all the tests that followed(see 3rd run curve). this phenomenon occurs with every first use of every sensor I tested.

    Because we do not know what causes this we would like to know if you might do. 

  • Hi Brian,

    Thank you for the detailed description. Let me try to run your experiment here and see if I am able to reproduce your results.

    Best Regards,

    Harsha

  • Hi Brian,

    Thank you again for reporting this issue. I was able to confirm your observations on a 5-unit sample of DRV5053CA devices. The worst-case VQ change I recorded was about 8mV peak-to-peak between saturating the parts at either end of the input range. The offset persists even after power cycling. Subsequently, I made inquiries about this and found out that the lead frame contains trace amounts of iron and nickel, which means it can be magnetized by strong fields. Please note that this will not be an issue on our upcoming linear Hall devices (samples available next month) as they use non-magnetic lead frames.

    Best Regards,
    Harsha
  • Hello Harsha,

    Thanks for confirming my observations! I would like to know if it is possible to pre-order these sensors? Or get some samples as soon as they are available, because we would need to implement the new sensors into the device which will also require testing. Also will the old sensor models still be sold after these new ones are available?

    Thanks a lot!

    Greetings,

    Brian Crutzen

    ACMIT Gmbh