SBAS644B April   2018  – June 2020 DRV5056

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Schematic
      2.      Magnetic Response
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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
  7. 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 Magnetic Response
      3. 7.3.3 Sensitivity Linearity
      4. 7.3.4 Ratiometric Architecture
      5. 7.3.5 Operating VCC Ranges
      6. 7.3.6 Sensitivity Temperature Compensation For Magnets
      7. 7.3.7 Power-On Time
      8. 7.3.8 Hall Element Location
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Selecting the Sensitivity Option
      2. 8.1.2 Temperature Compensation for Magnets
      3. 8.1.3 Adding a Low-Pass Filter
      4. 8.1.4 Designing for Wire Break Detection
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 What to Do and What Not to Do
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2 Detailed Design Procedure

This design example consists of a mechanical component that moves back and forth, an embedded magnet with the south pole facing the printed-circuit board, and a DRV5056. The DRV5056 outputs an analog voltage that describes the precise position of the component. The component must not contain ferromagnetic materials such as iron, nickel, and cobalt because these materials change the magnetic flux density at the sensor.

When designing a linear magnetic sensing system, always consider these three variables: the magnet, sensing distance, and range of the sensor. Select the DRV5056 with the highest sensitivity that has a BL (linear magnetic sensing range) that is larger than the maximum magnetic flux density in the application.

Magnets are made from various ferromagnetic materials that have tradeoffs in cost, drift with temperature, absolute maximum temperature ratings, remanence or residual induction (Br), and coercivity (Hc). The Br and the dimensions of a magnet determine the magnetic flux density (B) produced 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. Figure 32 shows diagrams for Equation 4 and Equation 5.

DRV5056 mag.gifFigure 32. Rectangular Block and Cylinder Magnets

Use Equation 4 for the rectangular block shown in Figure 32:

Equation 4. DRV5056 RectEQ.gif


Use Equation 5 for the cylinder shown in Figure 32:

Equation 5. DRV5056 CylEQ.gif

where

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