AS5304 Magnet Specification

2013-Sep [1-00]

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1

General Description

This specification defines the dimensional and magnetic properties of a multipole magnetic ring for

use with the AS5304 magnetic encoder for off-axis rotary applications.

Figure 1

AS5304 with multipole ring magnet for off-axis rotary motion sensing (not to scale)

Note:

The MR20-44 magnet contains only the magnetic ring (see picture on the right), the metal carrier is

shown for illustration purposes only

2

Multipole Ring Magnets for the AS5304

Figure 2 shows the proper placement of a multipole ring over the AS5304. The centerline of the

magnetic ring (median Hall sensor scan path) is located over the Hall array (see Figure 3).

The magnetic ring is designed such that the pole length lp matches the required length at the scan

path (typically the center) of the ring. The IC is oriented in perpendicular with respect to the rotation

center.

The correct measurement radius can be calculated by the number of poles of the magnet ring and

the specified pole length:

These figures can be determined by the code of the magnet: