AS5306AATSU austriamicrosystems, AS5306AATSU Datasheet - Page 9

• Manufacturer Part Number: AS5306AATSU
• Description: IC, LINEAR ENCODER, 12.3BIT, 20-TSSOP
• Manufacturer: austriamicrosystems
• Type: Linear Magneticr

Specifications of AS5306AATSU

• Ic Function: Encoder IC
• Supply Voltage Range: 4.5V To 5.5V
• Operating Temperature Range: -40°C To +125°C
• Digital Ic Case Style: TSSOP
• No. Of Pins: 20
• Termination Type: SMD
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS5304/AS5306 Integrated Hall IC for linear and off-axis rotary motion detection
8.1
When using the AS5304/AS5306 in an off-axis rotary application, a multi-pole ring magnet must be used. Resolution, diameter
and maximum speed depend on the number of pole pairs on the ring.
8.1.1
The angular resolution increases linearly with the number of pole pairs. One pole pair has a resolution (= interpolation factor) of
160 steps or 40 quadrature pulses.
Resolution [steps] = [interpolation factor] x [number of pole pairs]
Resolution [bit] = log (resolution[steps]) / log (2)
8.1.2
The length of a pole pair across the median of the multi-pole ring must remain fixed at either 4mm (AS5304) or 2.4mm
(AS5306). Hence, with increasing pole pair count, the diameter increases linearly with the number of pole pairs on the magnetic
ring.
Magnetic ring diameter = [pole length] * [number of pole pairs] / π
8.1.3
The AS5304/AS5306 use a fast interpolation technique allowing an input frequency of 5kHz. This means, it can process
magnetic field changes in the order of 5000 pole pairs per second or 300,000 revolutions per minute. However, since a magnetic
ring consists of more than one pole pair, the above figure must be divided by the number of pole pairs to get the maximum
rotation speed:
Maximum rotation speed = 300,000 rpm / [number of pole pairs]
Example: same as above: multi-pole ring with 22 pole pairs:
8.1.4
For linear motion sensing, a multi-pole strip using equally spaced north and south poles is used. The pole length is again fixed
at 2.0mm for the AS5304 and 1.2mm for the AS5306. As shown in 8.1.3 above, the sensors can process up to 5000 pole pairs
per second, so the maximum travelling speed is:
Maximum linear travelling speed = 5000 * [pole pair length]
Revision 1.5
Resolution and Maximum Rotating Speed
Example: multi-pole ring with 22 pole pairs
Resolution
Example: same as above: multi-pole ring with 22 pole pairs for AS5304
Ring diameter =
For the AS5306, the same ring would have a diameter of: 2.4 * 22 / 3.14 = 16.8mm
Max. speed = 300,000 / 22 = 13,636 rpm (this is independent of the pole length)
Example: linear multi-pole strip:
Max. linear travelling speed = 4mm * 5000 1/sec = 20,000mm/sec = 20m/sec
Max. linear travelling speed = 2.4mm * 5000 1/sec = 12,000mm/sec = 12m/sec
Resolution
Multi-pole Ring Diameter
Maximum Rotation Speed
Maximum Linear Travelling Speed
= 160x22 = 3520 steps per revolution
= 40x22 = 880 quadrature pulses / revolution
= 11.78 bits per revolution = 0.1023° per step
for AS5304: d = 4.0mm * number of pole pairs / π
for AS5306: d = 2.4mm * number of pole pairs / π
4 * 22 / 3.14 = 28.01mm (this number represents the median diameter of the ring, this is where the
Hall elements of the AS5304/AS5306 should be placed; see Figure 4)
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for AS5304
for AS5306
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