SLYS048B March 2023 – August 2024 TMAG6181-Q1
PRODUCTION DATA
The AMR sensor has two components that are sensitive to the in-plane magnetic field X and Y axes parallel to the chip surface. Figure 6-4 shows the AMR sensor with the differential sine and cosine outputs SIN_P, SIN_N, COS_P and COS_N. The outputs have an electrical range of 180 degrees. If the mechanical angle between the sensor reference and the direction of the magnetic field is θ, then the AMR outputs correspond to cosine 2θ and sine 2θ, respectively. For every 360° rotation of the external magnetic field, the AMR outputs provide two periods at 180° sensing range for each period. Hence, for a dipole magnet rotating at speed of f, the electrical output from the AMR sensor outputs can be at twice the frequency at 2f. Use Equation 1 to calculate the angle of the magnetic field using an arctangent2 function.
where
The AMR sensor is sensitive only to the direction of the magnetic field and has a wide operating magnetic field range. The voltage levels of the AMR outputs are independent of the absolute flux density as long as the magnetic flux density is above the minimum recommended operating fields.
Figure 6-5 shows the two integrated Hall sensors X and Y that are sensitive to the in-plane X and Y axes similar to the AMR sensor. The outputs Q1 and Q0 shows the digital outputs of both these sensors, respectively. Figure 6-5 shows both the Hall outputs reacting to the input field by going low when the field is higher than operating point (BOP) and going high when the field is lower than returning point (BRP).
For a rotating input magnetic field, with the Y and X components of BSIN and BCOS respectively, Figure 6-6 shows the response of the AMR and Hall sensors. The integrated X and Y Hall sensors provide digital outputs (Q1 and Q0, respectively). See the Functional Block Diagram. The Hall sensors have a 360° angle range compared to the 180° angle range of the AMR sensors.