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DRV425: sensor container/testing circuit

Part Number: DRV425

Hi,

I recently booked the drv425 sensor for a project. Now I'm wondering is there any method that does not use something like a pcb to test the sensor? Is there any container where I could put the sensor on and then testing it? If not, what is the best way to test the sensor?

Thank you

Haotian

  • Hello Haotian,

    I do not know a way you can test this without a PCB.  The DRV425 requires power and the feedback loop closed to function.  The DRV425EVM is a good place to start.  

    When testing offset you need to make sure there is no field present this can be accomplished by placing the device in a Zero Gauss Chamber.  Any external fields like the earth's field will change your measurements.

    For applying a field the best way that is to use a Helmholtz coil to generate a controlled field.  

    You can use the DRV425EVM in both of those to get good numbers.  Please be aware in the coil the axis of sensitivity of the DRV425 vs the field generated by the Helmholtz coil.

  • Hi Javier,

    EVM is a good suggestion. 

    I am curios about the offset testing you mentioned. Is this test for sensor calibration?

    A follow-up question: we are going to measure the magnetic fields of home powerline radiations, which is a weak signal in uT,  we also wonder if this DRV425EVM is able to provide such precision. 

    Thanks.

  • Hello Xiaoxuan,

    The max offset of the sensor is 8uT at room.  Placing it in the Gauss chamber will give you way to calibrate the offset of the senor but you may get a larger filed from the earth.  I would suggest getting the offset in the environment it will be placed in.  The earth field could create about 60µT depending on orientation of the DRV425.

    The resolution will be dependent on noise.  See this post.  The DRV425EVM does not have the optimal components close to the device as they can become magnetized and create a very small offset.  Getting capacitor close to the device that are not made with magnetic material is difficult but as long as they don't get magnetized they will function fine.  If they are introduced to a large magnetic field they can get magnetized.  I have measured single digit µT offset using multiple DRV425EVM in a Gauss chamber.