SNOSCZ7B December   2015  – April 2024 LDC0851

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Interface Voltage Levels
    7. 5.7 Timing Requirements
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Basic Operation Mode
      2. 6.3.2 Threshold Adjust Mode
      3. 6.3.3 Setting the Threshold Adjust Values
      4. 6.3.4 Hysteresis
      5. 6.3.5 Conversion Time
      6. 6.3.6 Power-Up Conditions
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Active Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Sensor Design
        1. 7.1.1.1 Sensor Frequency
        2. 7.1.1.2 Sensor Design Procedure
    2. 7.2 Typical Application
      1. 7.2.1 Event Counting
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Coarse Position Sensing
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curves
      3. 7.2.3 Low Power Operation
        1. 7.2.3.1 Design Requirements
        2. 7.2.3.2 Detailed Design Procedure
        3. 7.2.3.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
        1. 7.4.2.1 Side by Side Coils
        2. 7.4.2.2 Stacked Coils
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.3 Setting the Threshold Adjust Values

To configure a threshold setting, connect a 49.9 kΩ resistor (R1) between VDD and the ADJ pin as shown in Figure 6-4. The threshold is determined by the value of R2 as shown in the Table 6-1 below. R1 and R2 should be 1% or tighter tolerance resistors with a temperature coefficient of <50 ppm/°C.

Table 6-1 Resistor Values for ADJ Code
ADJ CodeR2 (kΩ)
13.32
25.11
37.15
49.31
511.5
614
716.5
819.6
922.6
1026.1
1130.1
1234
1339
1444.2
1549.9

The switching distance for each ADJ code can be approximated with the following formula:

Equation 1. GUID-FB41608E-72A7-407D-B4FA-F222FC561265-low.gif

where:

  • dswitch is the approximated switching distance threshold
  • dcoil is the coil diameter, in the same units as dswitch
  • ADJCode is the desired value from Table 6-1

For example, consider a coil with a diameter of 10 mm: An ADJ code of 1 will yield a switching distance of 3.75 mm and for a code of 15 a switching distance of 0.25 mm. This method helps reduce the effort needed to design the coil ratio precisely for a specific switching distance. It should be noted that the maximum sensing distance is determined almost entirely by the diameter of the coil for circular coils or by the minimum outer dimension for rectangular coils.