MA704 – 10-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS

MA704 Rev. 1.0

www.MonolithicPower.com

21

9/27/2017

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Figure 22: Relation between the Error Measured

with BCT = 0 and the Magnet Ratio k

Sensor Orientation

From the dot marked on the package, it is

possible to know whether the radial field is

aligned with the sensor coordinate X or Y (see

Figure 23).

Figure 23: Package Top View with X and Y Axes

Determine which axis needs to be reduced (see

the qualitative field distribution around a ring in

Figure 19). For instance, with the arrangement

depicted in Figure 23, the field along the sensor

Y direction is tangential and weaker. The X-axis

should be reduced (ETX = 1 and ETY = 0). Note

that if both ETX and ETY are set to 1, the current

bias is reduced in both directions the same way

(i.e.: without side-shaft correction) (see Table

14).

Table 14: Trimming Direction Parameters

ETX

Enable Trimming of the X-Axis

0

Disabled

1

Enabled

ETY

Enable Trimming of the Y-Axis

0

Disabled

1

Enabled

Magnetic Field Thresholds

The magnetic flags (MGL and MGH) indicate

that the magnetic field at the sensor position is

out a range defined by the lower (MGLT) and

upper magnetic field thresholds (MGHT) (see

Figure 24).

Figure 24: MGH and MGL Signals as a Function

of the Field Strength

MagHys, the typical hysteresis on the signals

MGH and MGL is 6mT. The MGLT and MGHT

thresholds are coded on three bits and stored in

register 6 (see Table 15).

Table 15: Register 6

Register 6

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

MGLT

MGHT

-

-

The 3-bit values of MGLT and MGHT correspond

to the magnetic field (see Table 16).

Table 16: MGLT and MGHT: Binary to mT

Relation

MGLT or

From low to high

magnetic field

From high to low

magnetic field

000

26

20

001

41

35

010

56

50

011

70

64

100

84

78

101

98

92

110

112

106

111

126

120

NOTES:

7)

Valid for VDD=3.3V. If different then field threshold is scaled

by the factor VDD/3.3V.

8)

MGLT can have a larger value than MGHT.

The alarm flags MGL and MGH are available to

be read in register 27 (bit 6, bit 7), and their logic

state is also given at the digital output pins 11

and 16.

1

1.5

2

2.5

3

3.5

4

4.5

5

0

5

10

15

20

25

30

35

40

E (deg)