AS5134 DB austriamicrosystems, AS5134 DB Datasheet - Page 30

• Manufacturer Part Number: AS5134 DB
• Description: BOARD DEMO AS5134
• Manufacturer: austriamicrosystems

Specifications of AS5134 DB

• Sensor Type: Magnetic, Rotary Position
• Sensing Range: 360°
• Interface: USB
• Voltage - Supply: 5V USB or 9V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: AS5134
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Sensitivity: -

AS5134
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
8.5.2 Magnet Thickness
Figure 21
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 21. Relationship of Peak Amplitude vs. Magnet Thickness
As the graph in
Therefore, the recommended thickness of 2.5mm (at 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.
8.5.3 Axial Distance (Airgap)
Figure 22. Sinusoidal Magnetic Field generated by the Rotating Magnet
The recommended magnetic field, measured at the chip surface on a radius equal to the Hall sensor array radius (typ. 1.1mm) should be within
a certain range. This range lies between 45 and 75mT or between 20 and 80mT, depending on the encoder product.
Linear position sensors are more sensitive as they use weaker magnets. The allowed magnetic range lies typically between 5 and 60mT.
www.austriamicrosystems.com/AS5134
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 21
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
vertical
field
Bz amplitude vs. magnet thickness
B
0,4
0
thickness to diameter [h/d] ratio
0,6
d= 6mm x h= 2.5mm ref. magnet:
h/d = 0.42
Rel. amplitude = 100%
Revision 1.13
0,8
1,0
1,2
360º
1,4
1,6
1,8
30 - 40