TLE5012 datasheet(10/64 Pages) INFINEON

10 / 64 page

TLE5012

Functional Description

Final Data Sheet

V 1.0, 2010-11

Functional Description

2.1

General

The GMR sensor uses vertical integration. This means that the GMR-sensitive areas are integrated above the

logic portion of the TLE5012 device. These GMR elements change their resistance depending on the direction of

the magnetic field.

Four individual GMR elements are connected to one Wheatstone sensor bridge. These GMR elements sense one

of two components of the applied magnetic field:

•

X component, Vx (cosine) or the

•

Y component, Vy (sine)

The advantage of a full-bridge structure is that the amplitude of the GMR signal is doubled and temperature effects

cancel out each other.

Figure 1

Sensitive bridges of the GMR sensor

Note: In Figure 1, the arrows in the resistors represent the magnetic direction which is fixed in the Reference

Layer. If the external magnetic field is parallel to the direction of the Reference Layer, the resistance is

minimal. If they are anti-parallel, resistance is maximal.

The output signal of each bridge is only unambiguous over 180° between two maxima. Therefore two bridges are

oriented orthogonally to each other to measure 360°.

With the trigonometric function ARCTAN, the true 360° angle value can be calculated, based on the relationship

of X and Y signals.

Because only the relative values influence the result, the absolute magnitude of the two signals is of minor

importance. Therefore, it is possible to compensate for most external influences on the amplitudes.

VDD

GND

ADCX+

GMR Resistors

ADCX-ADCY+ADCY-

0°

90°

TLE5012 Datasheet(PDF) 10 Page - Infineon Technologies AG