as5045 austriamicrosystems, as5045 Datasheet - Page 14

• Manufacturer Part Number: as5045
• Description: 12-bit Programmable Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER
each pin must be connected to the positive supply at pin
16 (VDD5V).
By hardware: PWM output: The PWM output is a
constant stream of pulses with 1kHz repetition frequency.
In case of power loss, these pulses are missing
13 Angular Output Tolerances
13.1
Accuracy is defined as the error between measured
angle and actual angle. It is influenced by several
factors:
As a sum of all these errors, the accuracy with centered
magnet = (Err
±0.5 degrees @ 25°C (see Figure 21).
Misalignment
accuracy. Figure 20 shows an example of a 3D-graph
displaying non-linearity over XY-misalignment. The
center of the square XY-area corresponds to a centered
magnet (see dot in the center of the graph). The X- and
Y- axis extends to a misalignment of ±1mm in both
directions. The total misalignment area of the graph
covers a square of 2x2 mm (79x79mil) with a step size of
100µm.
For each misalignment step, the measurement as shown
in Figure 21 is repeated and the accuracy
(Err
the Z-axis in the 3D-graph.
Revision 1.2, 03-Oct-06
max
the non-linearity of the analog-digital converters,
internal gain and mismatch errors,
non-linearity due to misalignment of the magnet
– Err
Figure 21: Example of linearity error over 360°
Accuracy
-0.1
-0.2
-0.3
-0.4
-0.5
0.5
0.4
0.3
0.2
0.1
min
0
max
)/2 (e.g. 0.25° in Figure 21) is entered as
1
of
– Err
55
the
min
109
)/2 is specified as better than
magnet
163
217
further reduces
271
Linearity error with centered magnet [degrees]
325
Err
www.austriamicrosystems.com
m ax
379
the
433
487
541
The maximum non-linearity error on this example is
better than ±1 degree (inner circle) over a misalignment
radius of ~0.7mm. For volume production, the placement
tolerance of the IC within the package (±0.235mm) must
also be taken into account.
The total nonlinearity error over process tolerances,
temperature and a misalignment circle radius of 0.25mm
is specified better than ±1.4 degrees.
The magnet used for this measurement was a cylindrical
NdFeB (Bomatec® BMN-35H) magnet with 6mm diameter
and 2.5mm in height.
Err
Figure 20: Example of linearity error over XY misalignment
595
m in
6
°
5
4
3
649
2
1
0
703
Linearity Error over XY-misalignment [°]
757
transition noise
y
811
865
919
-1000
-800
973
-600
-400
-200
0
200
400
600
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x
800
1000