as5311 austriamicrosystems, as5311 Datasheet - Page 14

• Manufacturer Part Number: as5311
• Description: High Resolution Magnetic Linear Encoder
• Manufacturer: austriamicrosystems

AS5311
Data Sheet
8 3.3V / 5V Operation
The AS5311 operates either at 3.3V ±10% or at 5V ±10%. This is made possible by an internal 3.3V Low-
Dropout (LDO) Voltage regulator. The internal supply voltage is always taken from the output of the LDO,
meaning that the internal blocks are always operating at 3.3V.
For 3.3V operation, the LDO must be bypassed by connecting VDD3V3 with VDD5V (see Figure 11).
For 5V operation, the 5V supply is connected to pin VDD5V, while VDD3V3 (LDO output) must be buffered by a
2.2...10µF capacitor, which is supposed to be placed close to the supply pin.
The VDD3V3 output is intended for internal use only It must not be loaded with an external load.
The output voltage of the digital interface I/O’s corresponds to the voltage at pin VDD5V, as the I/O buffers are
supplied from this pin.
A buffer capacitor of 100nF is recommended in both cases close to pin VDD5V. Note that pin VDD3V3 must
always be buffered by a capacitor. It must not be left floating, as this may cause an instable internal 3.3V supply
voltage which may lead to larger than normal jitter of the measured angle.
Figure 11: Connections for 5V and 3.3V supply voltages
9 Magnet Specifications
9.1 Magnetization
The AS5311 accepts magnetic multi-pole strip or ring magnets with a pole length of 1.0mm. Recommended
magnet materials include plastic or rubber bonded ferrite or Neodymium magnets.
It is not recommended to use the AS5311 with other pole lengths as this will create additional nonlinearities.
Figure 12: Additional error from pole length mismatch
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Error
[µm]
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
750 800 850 900 950 1000 1050 1100 1150 1200 1250
AS5311 Systematic Linearity Error Caused by Pole
Length Deviation
Pole Length [µm]
Revision 1.00
Error [µm]
14 - 21