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DRV5032: When will the IC have the situation of the MIN and MAX Bop/Brp values?

Daniel Tong1
Prodigy 50 points
Part Number: DRV5032

Hello, TI engineers.

I've recently have some application demand related to the switch hall effect sensor, such as the DRV 5032 family, I need to place this IC in a suitbale position to feedback the ON/OFF signal with the mechanism movement. I have some questions related to the Bop/Brp parameters in the datasheet as below:

The datasheet shows that the Bop/Brp will have three kinds of valuse, MIN/TYPICAL/MAX value, for example, AJ's parameter is as below. I want to know, is this value variations caused by the process which means each lot will have a different values of the Bop and Brp, or this value is considering the impact of the tempearture variations. However, we can only see the typical value data in the B/T curve, I am wondering when the hall IC will have the situtaion of the MIN and MAX value for the Bop and Brp.

Thank you.

  • 0
    TI__Mastermind 22470 points

    Daniel,

    The answer here is both. The distribution for the BOP and BRP values you mention are qualified over the total temperature range, so temperature variation is taken into consideration here. That said, these parameters will also vary part to due to process variation, so you will need to design to BOP_max in your switch design to ensure that all devices will work in your design across the distribution. If it helps, the distribution is Gaussian from the typical value. 

    Check out this app note, as it is a great primer for getting started in these types of designs. For a simple ON/OFF configuration, I would recommend starting with section 4.1.

  • 0 in reply to Carolus Andrews
    Prodigy 50 points

    HI, Carolus

    Thanks for your quick feedback on this question, it is great help for me to undetstand this application.

    Besides, I have one more question for you, as you mentioned that we need to consider the worst case for the application, for example, if Brp is tend to reach the min value of 3mT, what is the value of Bop in this condition, is it also in a min value, I want to know if the the magnetic hysteresis is translation from typical to worst case with both Bop and Brp?

    Thank you.

  • 0 in reply to Daniel Tong1
    TI__Mastermind 22470 points

    Daniel,

    This is where the hysteresis value in the datasheet becomes relevant. 

    Note, as I said above, that your BOP and BRP points can fall anywhere inside the published min/max values of the datasheet. That said, the BHYS spec says that you will never see a part that has both max BOP and min BRP. For example, If the part you receive were to exhibit BOP max, which is 9.5mT, then by the BHYS spec, the worst case BRP that the part would have is 6.5mT (8.1mT typical), as this is the BOP max - BHYS max. Does this make sense?

  • 0 in reply to Carolus Andrews
    Prodigy 50 points

    HI, Carolus

    Yes, it is more clear for my application, actually, the AJ performance is very stable with the temp variation, so I am wondering if the differenet initial value of the Bop and Brp of the signle unit  is more impacted by the process. If it is, then I will need to check the Bop and Brp in the IQC process, I will use the calibration method to modify the distance of each unit to control the tolerance of the Bop and Brp. If not, what would be the cause for the Bop and Brp variation in the application? For eaxmple, the initial value of Bop and Brp is 7mT and 5.6mT, when would it be changed to the worst case like 4mT and 3mT.

    Thank you for your support always. 

  • 0 in reply to Daniel Tong1
    TI__Mastermind 22470 points

    Daniel,

    I am in agreeance, that process variation will most likely be a larger influencing factor than temperature here. That said, make sure you take the magnet into account as well. Based on the magnet you choose, the flux of the magnet will also increase/decrease with temperature, potentially also adjusting the tolerance of the system.