www.ams.com/AS5030

Revision 2.4

39 - 44

AS5030

Datasheet - Application In formatio n

Figure 34. Typical Error Curve of INL Error Over Lateral Displacement (including quantization error)

8.9.3 Magnet Size

Figure 32 to Figure 34 in this chapter describe a cylindrical magnet with a diameter of 6mm. Smaller magnets may also be used, but since the

poles are closer together, the linear range will also be smaller and consequently the tolerance for lateral misalignment will also be smaller.

If the ± 0.25mm lateral misalignment radius (rotation axis to IC package center) is too tight, a larger magnet can be used. Larger magnets have

a larger linear range and allow more misalignment. However at the same time the slope of the magnet is more flat which results in a lower

differential amplitude.

This requires either a stronger magnet or a smaller gap between IC and magnet in order to operate in the amplitude-controlled area (AGC > 0

and AGC < 63).

In any case, if a magnet other than the recommended 6mm diameter magnet is used, two parameters should be verified:



Verify that the magnetic field produces a sinusoidal wave, when the magnet is rotated. Note that this can be done with the SIN-/COS-

outputs of the AS5030, e.g. rotate the magnet at constant speed and analyze the SIN- (or COS-) output with an FFT-analyzer.

It is recommended to disable the AGC for this test.



sinewave tests described above may be re-run at defined X-and Y- misplacements of the magnet to determine the maximum acceptable

lateral displacement range.

It is recommended to disable the AGC for both these tests.

Note:

For preferred magnet suppliers, please refer to the ams website (Rotary Encoder section).

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INL [°]

X Displaceme nt [µm]

Y Displacem ent [µm ]

INL vs. Displacement: AS5030 for AGC24

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4,000-4,500

3,500-4,000

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0,000-0,500