AS5030 AB austriamicrosystems, AS5030 AB Datasheet - Page 28

• Manufacturer Part Number: AS5030 AB
• Description: BOARD ADAPTER AS5030
• Manufacturer: austriamicrosystems

Specifications of AS5030 AB

• Sensor Type: Magnetic, Rotary Position
• Sensing Range: 360°
• Interface: Serial
• Voltage - Supply: 5V
• Embedded: No
• Utilized Ic / Part: AS5030
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Sensitivity: -

AS5030
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
8.5.3 Magnetic Field Strength Indicators
The AS5030 is not only able to sense the angle of a rotating magnet, it can also measure the magnetic field strength (and hence the vertical
distance) of the magnet.
This extra feature can be used for several purposes:
The magnetic field strength information is available in two forms:
Magnetic Field Strength Hardware Indicator:
determined by the value of the AGC. If the AGC value is <3F
(3F
Magnetic Field Strength Software Indicator:
AGC information. The AGC is an automatic gain control that adjusts the internal signal amplitude obtained from the Hall elements to a constant
level. If the magnetic field is weak, e.g. with a large vertical gap between magnet and IC, with a weak magnet or at elevated temperatures of the
magnet, the AGC value will be high. Likewise, the AGC value will be lower when the magnet is closer to the IC, when strong magnets are used
and at low temperatures.
The best performance of the AS5030 will be achieved when operating within the AGC range. It will still be operational outside the AGC range, but
with reduced performance especially with a weak magnetic field due to increased noise.
Factors Influencing the AGC Value.
OTP Sensitivity Adjustment.
at normal operating temperature should be in the middle between minimum and maximum, hence it should be around 100000 (20
To facilitate the “vertical centering” of the magnet+IC assembly, the sensitivity of the AS5030 can be adjusted in the OTP register in 4 steps. A
sensitivity adjustment is recommended, when the AGC value at normal operation is close to its lower limit (around 00
setting is 00
8.5.4 “Pushbutton” Feature
Using the magnetic field strength software and hardware indicators described above, the AS5030 provides a useful method of detecting both
rotation and vertical distance simultaneously. This is especially useful in applications implementing a rotate-and-push type of human interface
(e.g. in panel knobs and switches).
The MagRngn output is low, when the magnetic field is below the low limit (weak or no magnet) and high when the magnetic field is above the
low limit (in-range or strong magnet).
A finer detection of a vertical distance change, for example when only short vertical strokes are made by the pushbutton, is achieved by
memorizing the AGC value in normal operation and triggering on a change from that nominal the AGC value to detect a vertical movement.
www.austriamicrosystems.com/AS5030
H
- as a safety feature by constantly monitoring the presence and proper vertical distance of the magnet
- as a state-of-health indicator, e.g. for a power-up self test
- as a pushbutton feature for rotate-and-push types of manual input devices
), the MagRngn output will be low (red range).
the initial strength of the magnet. Aging magnets may show a reducing magnetic field over time which results in an increase of the AGC
value. The effect of this phenomenon is relatively small and can easily be compensated by the AGC.
the vertical distance of the magnet. Depending on the mechanical setup and assembly tolerances, there will always be some variation of the
vertical distance between magnet and IC over the lifetime of the application using the AS5030. Again, vertical distance variations can be
compensated by the AGC
the temperature and material of the magnet. The recommended magnet for the AS5030 is a diametrically magnetized, 5-6mm diameter
NdFeB (Neodymium-Iron-Boron) magnet. Other magnets may also be used as long as they can maintain to operate the AS5030 within the
AGC range.
Every magnet has a temperature dependence of the magnetic field strength. The temperature coefficient of a magnet depends on the used
material. At elevated temperatures, the magnetic field strength of a magnet is reduced, resulting in an increase of the AGC value. At low
temperatures, the magnetic field strength is increased, resulting in a decrease of the AGC value.
The variation of magnetic field strength over temperature is automatically compensated by the AGC.
H
= low sensitivity.
To obtain best performance and tolerance against temperature or vertical distance fluctuations, the AGC value
In practical use, the AGC value will depend on several factors:
D13:D7 in the serial data that is obtained by command READ ANGLE contains the 6-bit
Pin MagRngn (#1) will be low, when the magnetic field is too weak. The switching limit is
H
, the MagRngn output will be high (green range), If the AGC is at its upper limit
Revision 2.1
H
). The default sensitivity
H
).
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