DRV5055: How to select the Magnet Material?

Hello James,

Thank you for using the TI forum.  Typically, the magnet size/shape and type/material are chosen to help get the desired magnetic field curve and strength seen at the sensor.  Different types of magnets have a lot of different properties, as shown here: https://buymagnets.com/content/upload/files/Magnet%20Characteristics.pdf, but Br is the main characteristic that affects the strength of the magnetic field in a head on approach.  Some other characteristics to think about are how the magnetic field changes with temperature. (See this video: https://training.ti.com/ti-precision-labs-magnetic-sensors-how-permanent-magnets-magnetic-field-changes-temperature?context=1139747-1139746-1137749-1139636-1137747). If you expect a large fluctuation in temperature, then you may want to go with a neodymium magnet, since our linear Hall sensors compensate for this temperature drift. 

The DRV5056 has another calculator tool that can help you for head on measurements and to help you get an idea of how different magnets affect the curve of the magnetic field. This can be found here: https://www.ti.com/lit/zip/sbac231.