AS5046ASSU austriamicrosystems, AS5046ASSU Datasheet - Page 27

• Manufacturer Part Number: AS5046ASSU
• Description: IC, MAGNETIC ROTARY ENCODER 12BIT SSOP16
• Manufacturer: austriamicrosystems
• Type: Magnetic Rotary Encoderr

Specifications of AS5046ASSU

• Ic Function: Encoder IC
• Supply Voltage Range: 3V To 3.6V, 4.5V To 5.5V
• Operating Temperature Range: -40°C To +125°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 16
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS5046 Programmable 360° Magnetic Angle Encoder – Preliminary Data Sheet
14 Alignment Mode
The alignment mode simplifies centering the magnet over
the chip to gain maximum accuracy and XY-alignment
tolerance.
This electrical centering method allows a wider XY-
alignment tolerance (0.485mm radius) than mechanical
centering (0.25mm radius) as it eliminates the placement
tolerance of the die within the IC package (+/- 0.235mm).
Alignment mode can be enabled with the falling edge of
CSn while PROG = logic high (Figure 19). The Data bits
D11-D0 of the serial interface change to a 12-bit
displacement amplitude output. A high value indicates
large X or Y displacement, but also higher absolute
magnetic field strength. The magnet is properly aligned,
when the difference between highest and lowest value
over one full turn is at a minimum.
Under normal conditions, a properly aligned magnet will
result in a reading of less than 128 over a full turn.
Stronger magnets or short gaps between magnet and IC
may show values larger than 128. These magnets are
still properly aligned as long as the difference between
highest and lowest value over one full turn is at a
minimum.
The MagInc and MagDec indicators will be = 1 when the
alignment mode reading is < 128. At the same time,
hardware pin MagRngn (#1) will be pulled to VSS.
The Alignment mode can be reset to normal operation
mode by a power-on-reset (cycle power supply) or by a
falling edge of CSn with PROG=low (see Figure 20).
Revision 1.1
Figure 19: Enabling the alignment mode
Figure 20: Exiting alignment mode
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15 Choosing the Proper Magnet
Typically the magnet should be 6mm in diameter and ≥2.5mm in
height. Magnetic materials such as rare earth AlNiCo, SmCo5 or
NdFeB are recommended.
The magnet’s field strength perpendicular to the die
surface should be verified using a gauss-meter. The
magnetic field B
circle with a radius of 1.1mm (R1), should be in the range
of ±45mT…±75mT. (see Figure 21).
Figure 21: Typical magnet and magnetic field distribution
Vertical field
component
Vertical field
component
Bv
v
at a given distance, along a concentric
0
360
N
(45…75mT)
R1
typ. 6mm diameter
R1 concentric circle;
radius 1.1mm
S
Magnet axis
Magnet axis
360
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