SLIA096 January   2022 DRV5021 , DRV5021-Q1 , DRV5023 , DRV5023-Q1 , DRV5032 , DRV5033 , DRV5033-Q1 , TMAG5123 , TMAG5123-Q1 , TMAG5124 , TMAG5124-Q1 , TMAG5231 , TMAG5328

 

  1.   Trademarks
  2. 1Introduction
  3. 2Design Process
    1. 2.1 Mechanical Implementation
    2. 2.2 Magnetic Implementation
    3. 2.3 Magnet Sensor Placement
    4. 2.4 Prototyping and Bench Testing
    5. 2.5 Layout
    6. 2.6 Bench Testing
    7. 2.7 Bench Results
    8. 2.8 Error Sources
      1. 2.8.1 Offsets
      2. 2.8.2 Roll, Yaw, and Pitch
      3. 2.8.3 Magnet Variation
      4. 2.8.4 Device Variation and Temperature Drift
      5. 2.8.5 External Fields
      6. 2.8.6 Nearby Material Influence
      7. 2.8.7 Bench Setup Error
  4. 3Summary

Bench Results

After collecting all the data, assess whether the results make sense and possibly find explanations for inconsistencies. Ideally, all of the data falls within the expected measurement range based upon the threshold bounds calculated in the preliminary design phase. Such data could be assessed in a chart similar to Figure 2-20.

Figure 2-20 Acceptable Measurement Range

Figure 2-21 shows the results accumulated for three boards that each have one DRV5033FA-based rocker-switch, one DRV5033AJ-based rocker-switch, and one DRV5033ZE-based rocker-switch. Each rocker had two Hall-effect switches. Notice that some of the measured thresholds were not within the bounds suggested by the calculator tool. This is something to be expected when only Hall-effect switch variation and temperature drift is considered and the tolerances of the PCB and rocker switch structure have loose tolerances. After recalculating the BOP maximum threshold with some reasonable offset of 0.5 mm for x, y, and z included, notice that the measurements logged are not too unreasonable. The Error Sources section delves into the various error sources and attempts to quantify their impact.

GUID-20211221-SS0I-NDDL-VXCF-B0ZPQJVKQ2CH-low.pngFigure 2-21 Bench Results vs Ideal Expectations
GUID-20211221-SS0I-XNMW-W990-QCM5Z8MXVHG6-low.pngFigure 2-22 Bench Results vs Bounds Including Offsets