High Accuracy GMR Wheel Speed and Direction Sensor IC

A19350

10

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Direction Changes, Vibrations, and

Anomalous Events

During normal operation, the A19350 will be exposed to changes

in the direction of target rotation (Figure 13), vibrations of the

target (Figure 14), and anomalous events such as sudden air

gap changes. These events cause temporary uncertainty in the

A19350’s internal direction detection algorithm.

The -xPx variant may transmit non-direction pulses during vibra-

tions, while the -xBx variant will not transmit any pulses during

vibrations.

N

S

N

S

N

S

N

N

S

Forward

Rota�on

Reverse

Rota�on

Direc�on

Change

Target Differen�al

Magne�c Profile

Figure 13: Direction Change Behavior

Figure 14: Vibration Behavior

NormalTarget Rotation

NormalTarget Rotation

S

S

S

NN

S

S

N

NN

[or

]

[or

]

W(REV)

t

Target

Differential

Magnetic

Profile

Vibration

[or

]

[or

]

[or

]

or