Texas Instruments TIDA-060040, Manual

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Angle (deg)
Mag
netic Flux
Den
sity (m
T)
0 45 90 135 180 225 270 315 360
-10
-8
-6
-4
-2
0
2
4
6
8
10
Bx
By
Figure 2-7. 20-mm Airgap Magnetic Field Inputs
The goal is to target an input near to the maximum of the linear magnetic sensing range of the target sensor.
With target devices such as
TMAG5170 and DRV5055 , it is necessary to allow for system tolerances while
selecting a sensor location to maximize SNR. Variations in device sensitivity, installation alignment, and magnet
quality can all have an impact on the observed field magnitude.
Sensitivity options for these two devices are shown in Table 2-1 .
Table 2-1. Linear Hall-Effect Sensor Input Ranges
DEVICE LINEAR MAGNETIC SENSING RANGE (B
L
)
TMAG5170A1 ±25 mT , ±50 mT, ±100 mT
TMAG5170A2 ±75 mT , ±150 mT, ±300 mT
DRV5055A1 DRV5055Z1 ±22 mT
DRV5055A2, DRV5055Z2 ±44mT
DRV5055A3, DRV5055Z3 ±88 mT
DRV5055A4, DRV5055Z4 ±176 mT
To allow for either device, a horizontal sensor range of 4.65 mm ( DRV5055 ) and 5.9 mm ( TMAG5170 ) from the
magnet face were selected to ensure at all possible positions that the input field would be within the B
L
of the
TMAG5170A1 using the ±100 mT setting and DRV5055A4 .
At this range, the expected input magnetic field components are shown in 5.9-mm Airgap Magnetic Field Inputs .
Angle (deg)
Mag
netic Flux
Den
sity (m
T)
0 45 90 135 180 225 270 315 360
-10
-8
-6
-4
-2
0
2
4
6
8
10
Bx
By
Figure 2-8. 5.9-mm Airgap Magnetic Field Inputs
System Overview www.ti.com
8 Absolute Angle Encoder Reference Design With Hall-Effect Sensors for
Precise Motor Position Control TIDUC07 – MARCH 2022
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