Datasheet
Table Of Contents
- 1 General Description
- 2 Key Features
- 3 Applications
- 4 Pin Assignments
- 5 Absolute Maximum Ratings
- 6 Electrical Characteristics
- 7 Detailed Description
- 7.1 Connecting the AS5030
- 7.2 Serial 3-Wire R/W Connection
- 7.3 Serial 3-Wire Read-only Connection
- 7.4 Serial 2-Wire Connection (R/W Mode)
- 7.5 Serial 2-Wire Continuous Readout
- 7.6 Serial 2-Wire Differential SSI Connection
- 7.7 1-Wire PWM Connection
- 7.8 Analog Output
- 7.9 Analog Sin/Cos Outputs with External Interpolator
- 7.10 3-Wire Daisy Chain Mode
- 7.11 2-Wire Daisy Chain Mode
- 8 Application Information
- 9 Package Drawings and Markings
- 10 Ordering Information
www.ams.com/AS5030 Revision 2.4 35 - 44
AS5030
Datasheet - Application Information
Figure 29 shows a typical example of an error curve over a full turn of 360° at a given X-Y displacement. The curve includes the quantization
error, transition noise and the system error. The total error is ~2.2° peak/peak (± 1.1°).
The sawtooth-like quantization error (see also Figure 28) can be reduced by averaging, provided that the magnet is in constant motion and there
are an adequate number of samples available. The solid bold line in Figure 29 shows the moving average of 16 samples. The INL (intrinsic non-
linearity) is reduced to from ~± 1.1° down to ~± 0.3°. The averaging however, also increases the total propagation delay, therefore it may be
considered for low speeds only or adaptive; depending on speed (see Position Error over Speed on page 30).
8.8.2 Vertical Distance of the Magnet
The chip-internal automatic gain control (AGC) regulates the input signal amplitude for the tracking-ADC to a constant value. This improves the
accuracy of the encoder and enhances the tolerance for the vertical distance of the magnet.
Figure 30. Typical Curves for Vertical Distance Versus ACG Value on Several Untrimmed Samples
As shown in Figure 30, the AGC value (left Y-axis) increases with vertical distance of the magnet.
Consequently, it is a good indicator for determining the vertical position of the magnet, for example as a push-button feature, as an indicator for a
defective magnet or as a preventive warning (e.g. for wear on a ball bearing etc.) when the nominal AGC value drifts away.
If the magnet is too close or the magnetic field is too strong, the AGC will be reading 0,
If the magnet is too far away (or missing) or if the magnetic field is too weak, the AGC will be reading 63 (3F
H
).
The AS5030 will still operate outside the AGC range, but the accuracy may be reduced as the signal amplitude can no longer be kept at a
constant level.
The linearity curve in Figure 30 (right Y-axis) shows that the accuracy of theAS5030 is best within the AGC range, even slightly better at small
airgaps (0.4mm ~ 0.8mm).
At very short distances (0mm ~ 0.1mm) the accuracy is reduced, mainly due to nonlinearities in the magnetic field.
At larger distances, outside the AGC range (~2.0mm ~ 2.5mm and more) the accuracy is still very good, only slightly decreased from the nominal
accuracy.
Since the field strength of a magnet changes with temperature, the AGC will also change when the temperature of the magnet changes. At low
temperatures, the magnetic field will be stronger and the AGC value will decrease. At elevated temperatures, the magnetic field will be weaker
and the AGC value will increase.
Linearity and AGC vs Airgap
0
8
16
24
32
40
48
56
64
0 500 1000 1500 2000 2500
Airgap [mm]
AGC value
1,0
1,2
1,4
1,6
1,8
2,0
2,2
Linearity [°]
sample#1 sample#2 sample#3 sample#4 Linearity [°]
[µm]