am8192b RLS, am8192b Datasheet - Page 13

• Manufacturer Part Number: am8192b
• Description: Angular Magnetic Encoder Ic
• Manufacturer: RLS

Data sheet
AM8192BD01_05
Issue 5, 14
Recommended magnet
The AM8192B can be supplied with a pre-selected magnet to ensure that optimum performance is achieved.
Alternatively, magnets can be sourced from other suppliers but they must conform to the following guidelines.
To select a suitable magnet it is important to know the properties of the sensors. Hall Sensors are only
sensitive to the perpendicular component of the magnetic flux density (B). The AM8192B has a Hall sensor
array arranged in a circle with a radius of 2.4 mm. The sensors are located on the surface of the silicon. The
nominal distance between the sensors and the magnet surface is 2.55 mm.
Magnets must be cylindrical in shape and diametrically polarized. The main criterion for magnet selection is
the modulation of the perpendicular component of magnetic flux density at the location of the sensors (B
and a low offset of magnet modulation.
* Typical value of B
** Bad quality magnets offset the B
We recommend that a magnet with the following parameters is used to provide the necessary modulation:
* Rare earth material magnets SmCo are recommended; however, NdFeB magnets can be used but they have different
© 2009 RLS d.o.o.
Parameter
Amplitude of B
Offset of B
Parameter
Diameter
Length
Material
Material remanence
Temperature coefficient
Curie temperature
the B
correctly with respect to the chip.
characteristics.
nAmpl
th
. 1 Tesla equals 10,000 Gauss.
n
January 2009
modulation
n
modulation
nAmpl
Fig. 19: Distribution of B
will give an analogue signal output with amplitude of 1 V. The amplitude of the signal is proportional to
Typ.
4
4
Sm2Co17
1.05
-0.03
720
Fig. 18: Distribution of the perpendicular component of B
n
modulation which results in increased integral nonlinearity when the magnet is not aligned
Symbol
B
B
nAmpl
nOffset
n
and its modulation if the magnet is rotated through 360°
Unit
mm
mm
T
% / °C
°C
Min.
-0.4
Typ.
40
Note
*
Max.
0.4
A
Unit
mT
mT
Note
*
**
associate company
n
13
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