ASIL-Compliant Hall-Effect Wheel Speed Sensor IC

with Speed and Direction Output

A19300

13

Allegro MicroSystems

955 Perimeter Road

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

www.allegromicro.com

Calibration and Direction Validation

When power is applied to the A19300, the built-in algorithm per-

forms an initialization routine. For a short period after power-on,

the device calibrates itself and determines the direction of target

rotation. Once the calibration routine is complete, the A19300

will transmit accurate speed and direction information.

Target Rotation

SS

NN

SS

NN

N

tor

W(FWD)

W(REV)

t

tW(FWD)

tW(FWD)

tW(FWD)

tor

W(FWD)

W(REV)

t

Target

Differential

Magnetic

Profile

t

Opposite

North Pole

Opposite

South Pole

Opposite

N→S Boundary

Opposite

S→N Boundary

ICC

Device Location at Power-On

Figure 11: Calibration Behavior (-xxBx Variant)