BU52078GWZ Datasheet, PDF (11/20 Pages) Rohm – Omnipolar Detection Hall IC

BU52078GWZ
Slide-by Position Sensing
Figure 20 depicts the slide-by configuration employed for position sensing. Note that when the gap (d) between the magnet
and the Hall IC is narrowed, the reverse magnetic field generated by the magnet can cause the IC to malfunction. As seen in
Figure 21, the magnetic field runs in opposite directions at Point A and Point B. Since the dual output omnipolar detection
Hall IC can detect the S-pole at Point A and the N-pole at Point B, the sensor can switch the output ON as the magnet slides
by in the process of position detection. Figure 22 plots magnetic flux density during the magnet slide-by. Although a reverse
magnetic field was generated in the process, the magnetic flux density decreases compared with the center of the magnet.
This demonstrates that slightly widening the gap (d) between the magnet and Hall IC reduces the reverse magnetic field and
prevents malfunctions.
10.0
Magnet
Slide
Flux
5.0
Reverse
L
Figure 20
d
Hall IC
Position of the Hall Element
(Reference)
A
B
0.0
S
N
Flux
Figure 21
-5.0
-10.0
0
2
4
6
8 10
Horizontal Distance from the Magnet
[mm]
UCSP35L1
Figure 22. Magnetic Flux Density vs Horizontal
Distance from the Magnet
0.4
0.4
0.25
(UNIT: mm)
Footprint Dimensions
(Optimize footprint dimensions to the board design and soldering condition)
UCSP35L1
SD
b3
e
Symbol
e
b3
SD
SE
Reference
value
0.40
φ0.20
0.20
0.20
(UNIT: mm)
I/O Equivalence Circuit
OUT1, OUT2
VDD
Figure 23
GND
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TSZ22111 • 15 • 001
The Hall ICs output pins are configured for CMOS (inverter)
output removing the need for external resistance and allow
direct connection to the host. Removing the need for external
resistors allows for reduction of the current that would
otherwise flow to the external resistor during magnetic field
detection thereby supporting an overall lower current
(micropower) operation.
11/16
TSZ02201-0M2M0F415030-1-2
24.Aug.2015 Rev.001