ZMT32

Issue 1 - June 2008

5

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© Zetex Semiconductors plc 2008

Operating principle

When a common-magnetic field is applied through the

ZMT32 the 2 internal magneto-resistive bridges are

affected slightly differently due to their 45° rotation to

one another. This 45° rotation enables the ZMT32 to

determine angular position, of a rotating magnetic

field.

When a rotating magnetic field is applied to the ZMT32

it will output 2 sinusoidal voltages that are:

•

proportional to the field strength applied

•

proportional to the supply voltage applied,

•

rotating at twice the angular position

•

90° apart (as seen below).

angular

position

of

the

magnetic

field

can

be

determined.

H

rot

1

0

O

GND1

8

GND2

7

6

5

1

2

3

4

α = 0°

Bridge

1

Bridge

2

-V

O1

-V

O2

V

cc1

V

cc2

GND1

GND2

+V

O1

+V

O2

1

-15

-10

-5

0

5

10

0

45

90

135

180

225

270

315

360

Cos 2

α

Sin 2

α

Sensor bridge 2

Sensor bridge 1