AS5045-ASST austriamicrosystems, AS5045-ASST Datasheet - Page 25

• Manufacturer Part Number: AS5045-ASST
• Description: IC ENCODER PROG 12-BIT 16-SSOP
• Manufacturer: austriamicrosystems
• Type: Linear, Rotary Encoder - Programmabler

Specifications of AS5045-ASST

• Sensing Range: 45mT ~ 75mT
• Voltage - Supply: 3 V ~ 3.6 V, 4.5 V ~ 5.5 V
• Current - Supply: 21mA
• Current - Output (max): 4mA
• Output Type: Digital, PWM, 12-Bit Serial
• Features: Programmable
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS5045-ASSTTR

AS5045
Data Sheet
15 Simulation Modeling
Figure 20. Arrangement of Hall Sensor Array on Chip (principle)
With reference to Figure 20, a diametrically magnetized permanent magnet is placed above or below the surface of
the AS5045. 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.
orthogonally related cosine vector of the magnetic field.
The angular displacement (Θ) of the magnetic source with reference to the Hall sensor array may then be modelled
by:
The ±0.5° angular error assumes a magnet optimally aligned over the center of the die and is a result of gain
mismatch errors of the AS5045. Placement tolerances of the die within the package are ±0.235mm in X and Y
direction, using a reference point of the edge of pin #1 (see Figure 20).
In order to neglect the influence of external disturbing magnetic fields, a robust differential sampling and ratiometric
calculation algorithm has been implemented. The differential sampling of the sine and cosine vectors removes any
common mode error due to DC components introduced by the magnetic source itself or external disturbing magnetic
fields. A ratiometric division of the sine and cosine vectors removes the need for an accurate absolute magnitude of
the magnetic field and thus accurate Z-axis alignment of the magnetic source.
The recommended differential input range of the magnetic field strength (B
the die. In addition to this range, an additional offset of ±5mT, caused by unwanted external stray fields is allowed.
www.austriamicrosystems.com
The differential signal Y1-Y2 will give a sine vector of the magnetic field. The differential signal X1-X2 will give an
Θ
=
arctan
(
(
X
Y
1
1
−
−
Y
X
2
2
)
)
±
0
5 .
°
Revision 1.7
(X1-X2)
, B
(Y1-Y2)
) is ±75mT at the surface of
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