AS5145A AMSCO [austriamicrosystems AG], AS5145A Datasheet - Page 26

• Manufacturer Part Number: AS5145A
• Description: 12-Bit Programmable Magnetic Rotary Encoder
• Manufacturer: AMSCO [austriamicrosystems AG]

AS5145
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
9.4.2 Magnet Placement
The magnet’s center axis should be aligned within a displacement radius Rd of 0.25mm from the defined center of the IC. The magnet may be
placed below or above the device. The distance should be chosen such that the magnetic field on the die surface is within the specified limits
(see Figure
recommended magnet material and dimensions (6mm x 3mm). Larger distances are possible, as long as the required magnetic field strength
stays within the defined limits.
However, a magnetic field outside the specified range may still produce usable results, but the out-of-range condition will be indicated by
MagINCn (pin 1) and MagDECn (pin 2),
Figure 20. Vertical Placement of the Magnet
9.5 Simulation Modeling
Figure 21. Arrangement of Hall Sensor Array on Chip (principle)
A diametrically magnetized permanent magnet is placed above or below the surface of the AS5145. The chip uses an array of Hall sensors to
sample the vertical vector of a magnetic field distributed across the device package surface. The area of magnetic sensitivity is a circular locus of
1.1mm radius with respect to the center of the die. The Hall sensors in the area of magnetic sensitivity are grouped and configured such that
orthogonally related components of the magnetic fields are sampled differentially.
The differential signal Y1-Y2 will give a sine vector of the magnetic field. The differential signal X1-X2 will give an orthogonally related cosine
vector of the magnetic field.
www.austriamicrosystems.com/AS5145
19). The typical distance “z” between the magnet and the package surface is 0.5mm to 1.5mm, provided the use of the
±0.235mm
2.433mm
(see Table
Die surface
AS5145 die
1).
1
3.9mm±0.235mm
N
Radius of circular Hall sensor
N
X1
Revision 1.10
Package surface
S
Y1
Y2
X2
Center of die
Z
0.576mm ± 0.1mm
1.282mm ± 0.15mm
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