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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 19). The typical distance “z” between the magnet and the package surface is 0.5mm to 1.5mm, provided the use of the

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), (see Table 1).

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.

N

S

N

Die surface

Package surface

Z

0.576mm ± 0.1mm

1.282mm ± 0.15mm

Y1

Y2

X1

X2

Center of die

Radius of circular Hall sensor

AS5145 die

2.433mm

±0.235mm

3.9mm±0.235mm

1