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[v2-00] 2017-May-03

AS5304/AS5306 − Application Information

Maximum Rotation Speed

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

300000 revolutions per minute. However, since a magnetic ring

consists of more than one pole pair, the above value must be

divided by the number of pole pairs to get the maximum

rotation speed:

Maximum rotation speed = 300000 rpm / [number of pole pairs]

Example: (same as above) Multi-pole ring with 22 pole pairs:

Maximum speed = 300000 / 22 = 13636 rpm (this is independent

of the pole length)

Maximum Linear Travelling Speed

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 Maximum Rotation Speed 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]

Example: Linear multi-pole strip:

Maximum linear travelling speed = 4mm * 5000 1/s =

20000mm/s = 20m/s {for AS5304}

Maximum linear travelling speed = 2.4mm * 5000 1/s =

12000mm/s = 12m/s {for AS5306}

AS5304 Arkusz danych(PDF) 22 Page - ams AG