High-Accuracy, Pulse-Width or AK Protocol

Hall-Effect Wheel Speed and Direction Sensor IC

A19302

13

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Direction Changes, Vibrations,

and Anomalous Events

During normal operation, the A19302 will be exposed to changes in

the direction of target rotation (Figure 12), vibrations of the target

(Figure 13), and anomalous events such as sudden air gap changes.

During calibration, output pulses with direction information are

immediately transmitted to the output. Depending on target design,

air gap, and the phase of the target, direction may be momentarily

incorrect. Following a direction change in running mode, direction

changes are immediately transmitted to the output.

NormalTarget Rotation

NormalTarget Rotation

S

S

S

NN

S

S

N

NN

Target

Differential

Magnetic

Profile

Vibration

Figure 12: Direction Change Behavior

Figure 13: Vibration Behavior

N

S

N

S

N

S

N

N

S

Forward

Rota�on

Reverse

Rota�on

Direc�on

Change

Target Differen�al

Magne�c Profile

ICC