SLYS048A March   2023  – February 2024 TMAG6181-Q1

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 Magnetic Characteristics
    7. 5.7 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 Magnetic Flux Direction
      2. 6.3.2 Sensors Location and Placement Tolerances
      3. 6.3.3 Magnetic Response
      4. 6.3.4 Parameters Definition
        1. 6.3.4.1 AMR Output Parameters
        2. 6.3.4.2 Transient Parameters
          1. 6.3.4.2.1 Power-On Time
        3. 6.3.4.3 Hall Sensor Parameters
        4. 6.3.4.4 Angle Accuracy Parameters
      5. 6.3.5 Automatic Gain Control (AGC)
      6. 6.3.6 Turns Counter
        1. 6.3.6.1 Rotation Tracking
      7. 6.3.7 Safety and Diagnostics
        1. 6.3.7.1 Device Level Checks
        2. 6.3.7.2 System Level Checks
    4. 6.4 Device Functional Modes
      1. 6.4.1 Operating Modes
        1. 6.4.1.1 Active Mode
        2. 6.4.1.2 Active-Turns Mode
        3. 6.4.1.3 Low-Power Mode
        4. 6.4.1.4 Sleep Mode
        5. 6.4.1.5 Fault Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Power Supply as the Reference for External ADC
      2. 7.1.2 AMR Output Dependence on Airgap Distance
      3. 7.1.3 Calibration of Sensor Errors
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Designing with Multiple Sensors
          1. 7.2.2.1.1 Designing for Redundancy
          2. 7.2.2.1.2 Multiplexing Multiple Sensors
      3. 7.2.3 Application Curve
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.1.3 Calibration of Sensor Errors

The TMAG6181-Q1 is factory-calibrated for the best angular accuracy. Some of the electrical errors from the sensor that impact the angle accuracy can be calibrated out for achieving the best performance. Figure 7-23 shows the impact of the different sensor error parameters such as offset, amplitude mismatch and orthogonality error on the angle accuracy.

GUID-20220627-SS0I-BQMH-R9X6-KDTPSJ1RN9SP-low.svg Figure 7-1 Angle Accuracy Impact Owing to Sensor Electrical Errors (a) Offset Error (b) Amplitude Mismatch Error (c) Orthogonality Error

Based on the parameters defined in AMR Output ParametersHall Sensor Parameters, the angle from the AMR sensors is given by Equation 17:

Equation 17. θ = a r c t a n 2   ( A s i n   s i n ( 2 θ )   +   V o f f s e t _ s i n A c o s   c o s ( 2 θ )   +   V o f f s e t _ c o s   ) 2

where

  • Voffset_sin and Voffset_cos are the differential offsets of the sine and cosine outputs
  • Asin and Acos are the differential amplitude of the sine and cosine outputs

The impact of the angle accuracy owing to the orthogonality error and the hysteresis errors is negligible for the TMAG6181-Q1 and can be ignored.

To calibrate the offset and amplitude mismatch errors, the magnetic field rotates over the entire range and the sine and cosine outputs are sampled continuously to obtain the minimum and maximum values of the outputs.

Users can calculate the average of the minimum and maximum values of the respective outputs across the full angle range to find the offset error of the sine and cosine outputs. Use Equation 18 and Equation 19 to calculate the offset correction parameters for sine and cosine.

Equation 18. V o s _   s i n _ c a l = V s i n ( m a x )   +   V s i n ( m i n )   2
Equation 19. V o s _   c o s _ c a l = V c o s ( m a x )   +   V c o s ( m i n )   2

Users can calculate the difference of the minimum and maximum values of the respective outputs across the full angle range to find the amplitude of the sine and cosine outputs. Use Equation 20 to calculate the amplitude correction parameters for sine and cosine.

Equation 20. A c o r r = 1 - V s i n ( m a x )   –   V s i n ( m i n )   V c o s ( m a x )   –   V c o s ( m i n )