as5215 austriamicrosystems, as5215 Datasheet - Page 11

• Manufacturer Part Number: as5215
• Description: Programmable 360? Magnetic Angle Encoder With Buffered Sine & Cosine Output Signals
• Manufacturer: austriamicrosystems

AS5215
Data Sheet - D e t a i l e d D e s c r i p t i o n
7.1.2 Magnet Thickness
Figure 6
relation to the thickness of the magnet. The X-axis shows the ratio of magnet thickness (or height) [h] to magnet diameter [d] and the Y-axis
shows the relative peak amplitude with reference to the recommended magnet (d=6mm, h=2.5mm). This results in an h/d ratio of 0.42.
Figure 6. Relationship of Peak Amplitude vs. Magnet Thickness
As the graph in
Therefore, the recommended thickness of 2.5mm (@6mm diameter) should be considered as the low limit with regards to magnet thickness.
It is possible to get 40% or more signal amplitude by using thicker magnets. However, the gain in signal amplitude becomes less significant for h/
d ratios >~1.3. Therefore, the recommended magnet thickness for a 6mm diameter magnet is between 2.5 and ~8 mm.
www.austriamicrosystems.com/AS5215
shows the relationship of the peak amplitude in a rotating system (essentially the magnetic field strength of the Bz field component) in
160%
140%
120%
100%
80%
60%
40%
20%
0%
Figure 6
0,0
of a cylindrical diametric magnet with 6mm diameter
shows, the amplitude drops significantly at h/d ratios below this value and remains relatively flat at ratios above 1.3.
0,2
Bz amplitude vs. magnet thickness
0,4
thickness to diameter [h/d] ratio
0,6
d= 6mm x h= 2.5mm ref. magnet:
h/d = 0.42
Rel. amplitude = 100%
0,8
Revision 1.5
1,0
1,2
1,4
1,6
1,8
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