AS5040_1 AMSCO [austriamicrosystems AG], AS5040_1 Datasheet - Page 26

• Manufacturer Part Number: AS5040_1
• Description: 10Bit 360 Programmable Magnetic Rotary Encoder
• Manufacturer: AMSCO [austriamicrosystems AG]

AS5040
Data Sheet
18 Angular Output Tolerances
Accuracy
Accuracy is defined as the error between measured angle and actual angle. It is influenced by several factors:
As a sum of all these errors, the accuracy with centered magnet = (Err
degrees @ 25°C (see Figure 25).
Misalignment of the magnet further reduces the accuracy. Figure 24 shows an example of a 3D-graph displaying non-
linearity over XY-misalignment. The center of the square XY-area corresponds to a centered magnet (see dot in the
center of the graph). The X- and Y- axis extends to a misalignment of ±1mm in both directions. The total misalignment
area of the graph covers a square of 2x2 mm (79x79mil) with a step size of 100µm.
For each misalignment step, the measurement as shown in Figure 25 is repeated and the accuracy
(Err
Figure 24: Example of Linearity Error over XY Misalignment
The maximum non-linearity error on this example is better than ±1 degree (inner circle) over a misalignment radius of
~0.7mm. For volume production, the placement tolerance of the IC within the package (±0.235mm) must also be
taken into account.
The total nonlinearity error over process tolerances, temperature and a misalignment circle radius of 0.25mm is
specified better than ±1.4 degrees.
The magnet used for this measurement was a cylindrical NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter
and 2.5mm in height.
www.austriamicrosystems.com
max
– Err
the non-linearity of the analog-digital converters,
internal gain and mismatch errors,
non-linearity due to misalignment of the magnet
min
)/2 (e.g. 0.25° in Figure 25) is entered as the Z-axis in the 3D-graph.
6
°
5
4
3
2
1
0
Linearity Error over XY-misalignment [°]
y
Revision 2.10
-1000
-800
-600
-400
max
-200
0
200
400
– Err
600
x
800
1000
min
)/2 is specified as better than ±0.5
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