SLVSDC7G April 2017 – July 2024 DRV5032
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
When designing a digital-switch magnetic sensing system, consider these three variables: the magnet, sensing distance, and threshold of the sensor.
The DRV5032 device has a detection threshold specified by parameter BOP. To reliably activate the sensor, the magnet must apply greater than the maximum specified BOP. In such a system, the sensor typically detects the magnet before the magnet moves to the closest position. When the magnet moves away from the sensor, the magnet must apply less than the minimum specified BRP to reliably release the sensor.
Magnets are made from various ferromagnetic materials that have trade-offs in cost, drift with temperature, absolute max temperature ratings, remanence or residual induction (Br), and coercivity (Hc). The Br and the dimensions of a magnet determine the magnetic flux density (B) the magnet produces in 3-dimensional space. For simple magnet shapes, such as rectangular blocks and cylinders, there are simple equations that solve B at a given distance centered with the magnet.
Use Equation 1 for the rectangular block shown in Figure 8-2:
Use Equation 2 for the cylinder shown in Figure 8-2:
where
An online tool that uses these formulas is located at http://www.ti.com/product/drv5033.
All magnetic materials generally have a lower Br at higher temperatures. Make sure the systems have margin to account for this, as well as for mechanical tolerances.