AS5130 Datasheet, PDF (21/41 Pages) ams AG – 8 Bit Programmable Magnetic Rotary Encoder with Motion Detection & Multiturn

AS5130
Data Sheet - Detailed Description
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 AS5130. Again, vertical distance variations can be compensated by the AGC.
The temperature and material of the magnet. The recommended magnet for the AS5130 is a diametrically mag-
netized 6mm diameter magnet. Other magnets may also be used as long as they can maintain to operate the
AS5130 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 tem-
perature is automatically compensated by the AGC.
OTP Sensitivity Adjustment
To obtain best performance and tolerance against temperature or vertical distance fluctuations, the AGC value at
normal operating temperature should be in the middle between minimum and maximum, hence it should be around 32
(20H). To facilitate the “vertical centering” of the magnet+IC assembly, the sensitivity of the AS5130 can be adjusted in
the OTP register in 8 steps (see Table 10). The OTP sensitivity setting corresponds to the customer register setting
gain <2:0>.
“Pushbutton” Feature
Using the magnetic field strength software and hardware indicators described above, the AS5130 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 CAO 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.
Figure 15. Magnetic Field Strength Indicator
+5V
VDD
VDD
1k
LED1
Output
Output
I/O
VSS
VDD
CAO
CS _{AASS55113300 100n}
DCLK
DIO
C1 VSS
VSS
High Speed Operation
The AS5130 is using a fast tracking ADC (TADC) to determine the angle of the magnet. The TADC has a tracking rate
of 1.15µs (typ).
www.austriamicrosystems.com
Revision 1.00
21 - 41