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

6.3.5 Automatic Gain Control (AGC)

To reduce the drift of the AMR sensor outputs across temperature, the TMAG6181-Q1 features an automatic gain control circuitry where the device changes the gain of the output drivers to keep the final output within an appropriate voltage range on SIN_P, SIN_N, COS_P and COS_N. The AGC block uses the square root of the sum of the squared amplitudes of the two channels to sense amplitude of output signals and set gain selection. This means that the AGC block sets the gain for sine and cosine channels such that the peak-to-peak amplitude of single-ended voltages (VOUT) is within the range listed in Specifications. The AGC block changes the gain of both the sine and cosine channels simultaneously and does not affect the angle accuracy.

If the outputs are out of the intended operating range, the AGC block changes the gain of the sine and cosine channels by a step size of ±1% VCC at an interval of tagc_update, approximately one second, as defined in Specifications. Figure 6-12 shows the differential AMR outputs for a continuously rotating input field. The shaded area represents the 'No AGC Control' band that represents ±5% of VCC and is centered at 60% of VCC. Notice that the AGC loop reduces the gain of the sine and cosine channels and updates the amplitude of the sine and cosine signals when drift outside of the shaded region at a step size of 1% VCC. If the outputs remain within the shaded region, then no action is taken by the AGC control loop.

GUID-20220627-SS0I-6VV8-QPDX-LZVVHWKLKNMK-low.svgFigure 6-12 Timing Diagram Showing the Operation of Automatic Gain Control