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TMAG5124: Minimum distance of TMAG5124

Part Number: TMAG5124
Other Parts Discussed in Thread: , DRV5055

I'm looking for a product that starts at 0mm and switches when it reaches 1mm.
I have identified the TMAG5124 product.
I checked the datasheet example to have a minimum magnet distance of 3 cm.

I have a question.

Can I calibrate the TMAG5124 product with TMAG5124EVM so that the switch operates when the magnet reaches 0mm to 1mm?

Can you tell me the minimum and maximum magnetic distance of TMAG5124?


  • Thank you for reaching out.  With TMAG5124 (or any Hall effect switch) the switching distance depends entirely on the magnetic flux density at the sensor location.  The magnetic flux density is a function of the magnet geometry and material properties and so you cannot determine the exact minimum distance without this information.  Typically what you will be interested in are BOP Max and BRP Min.  As BOP and BRP do have some manufacturing variation to them, it is typically safest to design around the worst case conditions.  BOP Max represents the largest field required to activate a sensor while BRP Min represents the smallest field required to release the output back to the neutral state.  Some hysteresis is naturally built in to prevent output toggling when the magnet is fixed near the BOP threshold.

    There are some useful online calculators you might consider in your application.  For instance, you might investigate the DRV5055 device page which has a calculator that will estimate the field for various head on approaches (where the sensor is aligned to the polarization of the magnet).  However, you may find you are interested in a different approach.

    K&J Magnetics has a useful 2D calculator which will estimate the field surrounding an axially magnetized cylinder.  You can find this tool here

    Additionally there is another tool I am aware of which is capable of assisting with calculations in 3D space surrounding a magnet which you can find at the next link.  This tool does support a variety of magnet polarizations and shapes.  You will need to navigate through the web tool to find the magnet type that best fits your setup.

    TMAG5124 does not have any manual calibration feature.  The only way to adjust your switching distance will be to adjust the position of the magnet relative to the sensor or to change the magnet size and/or material.