SLVSDC7G April   2017  – July 2024 DRV5032

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Magnetic Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Magnetic Flux Direction
      2. 7.3.2 Device Version Comparison
        1. 7.3.2.1 Magnetic Threshold
        2. 7.3.2.2 Magnetic Response
        3. 7.3.2.3 Output Type
        4. 7.3.2.4 Sampling Rate
      3. 7.3.3 Hall Element Location
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Output Type Tradeoffs
    2. 8.2 Typical Applications
      1. 8.2.1 General-Purpose Magnet Sensing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Three-Position Switch
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.1.2 Detailed Design Procedure

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.

DRV5032 Rectangular Block and Cylinder Magnets Figure 8-2 Rectangular Block and Cylinder Magnets

Use Equation 1 for the rectangular block shown in Figure 8-2:

Equation 1. B → =   B r π a r c t a n W L 2 D 4 D 2 + W 2 + L 2   - a r c t a n W L 2 D + T 4 D + T 2 + W 2 + L 2

Use Equation 2 for the cylinder shown in Figure 8-2:

Equation 2. B → =   B r 2 D + T 0.5 C 2 + D + T 2   - D 0.5 C 2 + D 2

where

  • W is width.
  • L is length.
  • T is thickness (the direction of magnetization).
  • D is distance.
  • C is diameter.

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.