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DRV425: Nulling Earth's Magnetic Field

Part Number: DRV425 there any way to remove or filter the DRV425's response to the earth's mag field?  I'm attempting to detect low level AC-generated magnetic fields by increasing the value of R1 on the evaluation board, however, that also increases the earth-generated field which saturates the output. For example, if the earth's field provides 4.5 volts on the output it leaves only 0.5 volts of headroom for my AC-generated magnetic signal.  Appreciate any assistance, thank you.   

  • Hello Art,

    One way to do this is to shield it away by diverting the field not wanted away by enclosing the system with magnetic shielding material.  This is the most robust solution.  Just and FYI when shielding magnetic fields it is actually just creating a different path for the field to travel. 

    Another way is to supply a DC current that negates the DC field from the earth.  This will work if the DRV425 is not moving relative to the field of the earth.  The other method is more robust and will divert any other unwanted fields.  

    Be aware that magnetic material will also change the field you are trying to measure and may want to verify with simulations.  For best location and material properties.