TLE4925 Datasheet, PDF (14/25 Pages) Infineon Technologies AG – Differential Hall Sensor

PRELIMINARY
Application Configurations
Two possible applications are shown in Figure 8 and Figure 9 (Toothed and Magnet
Wheel).
The difference between two-wire and three-wire application is shown in Figure 12 for
the TLE4925C and in Figure 13 for the TLE4925.
Gear Tooth Sensing
In the case of ferromagnetic toothed wheel application the IC has to be biased by the
south or north pole of a permanent magnet (e.g. SmCO₅ (Vacuumschmelze VX145))
with the dimensions 8 mm × 5 mm × 3 mm) which should cover both Hall probes.
The maximum air gap depends on
- the magnetic field strength (magnet used; pre-induction) and
- the toothed wheel that is used (dimensions, material, etc.; resulting differential field).
a centered distance
S
of Hall probes
b Hall probes to
N
IC surface
L IC surface to
tooth wheel
a = 2.5 mm
b = 0.3 mm
Figure 8 Sensor Spacing
Conversion DIN – ASA
m = 25.4 mm/p
T = 25.4 mm CP
DIN
d diameter (mm)
z number of teeth
m module m = d/z (mm)
T pitch T = π × m (mm)
ASA
p diameter pitch p = z/d (inch)
PD pitch diameter
PD = z/p (inch)
CP circular pitch CP = 1 inch × π/p
Figure 9 Toothed Wheel Dimensions
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