3059 Datasheet, PDF (7/8 Pages) Allegro MicroSystems – HALL-EFFECT GEAR-TOOTH SENSORS -AC COUPLED

3059 AND 3060
HALL-EFFECT
GEAR-TOOTH SENSORS
—AC COUPLED
2000
1500
1000
500
0
-500
-1000
-1500
-2000
0
Figure 4
DIFFERENTIAL FLUX DENSITY
200
150
100
50
0
-50
0.025
0.050
0.075
0.100
AIRGAP FROM PACKAGE FACE IN INCHES
0.125
Dwg. GH-035
-100
-150
-200
0.070
0.080
0.090
0.100
0.110
AIRGAP FROM PACKAGE FACE IN INCHES
0.120
Dwg. GH-036
Ferrous Targets. The best ferrous targets are made
of cold-rolled low-carbon steel. Sintered-metal targets are
also usable, but care must be taken to ensure uniform
material composition and density.
The teeth or slots of the target should be cut with a
slight angle so as to minimize the abruptness of transition
from metal to air as the target passes by the sensor.
Sharp transitions will result in magnetic overshoots that
can result in false triggering.
Gear teeth larger than 0.10” (2.54 mm) wide and at
least 0.10” (2.54 mm) deep provide reasonable working
air gaps and adequate change in magnetic field for
reliable switching. Generally, larger teeth and slots allow
a larger air gap. A gear tooth width approximating the
spacing between sensors (0.088” or 2.24 mm) requires
special care in the sytem design and assembly tech-
niques.
Figure 5
SENSOR LOCATIONS
(±0.005” [0.13 mm] die placement)
ACTIVE AREA DEPTH
0.014"
0.37 mm
NOM
0.087"
2.20 mm
0.083"
2.10 mm
0.075"
1.91 mm
E1
E2
A
BRANDED
SURFACE 1
2
3
4
5
Dwg. MH-007D