BU52075GWZ Datasheet, PDF (10/20 Pages) Rohm – Omnipolar Detection Hall IC

BU52075GWZ
Intermittent Operation at Power ON
Power ON
VDD
Supply Current
(Intermittent Action)
Startup Time
OUT
(No Magnetic
Field Present)
OUT
(Magnetic
Field Present)
Indefinite
Interval
Indefinite
Interval
Standby Time
Startup Time
High
Low
Standby Time
Figure 17
The dual output omnipolar detection Hall IC adopts an intermittent operation method in detecting the magnetic field during
startup, as shown in Figure 17. The IC outputs to the appropriate terminal based on the detection result and maintains the
output condition during the standby period. The time from power ON until the end of the initial startup period is an indefinite
interval, but it cannot exceed the maximum period of 100ms. To accommodate the system design, the Hall IC output read
should be programmed within 100ms of power ON, but after the time allowed for the period, ambient temperature, and
supply voltage.
Magnet Selection
Of the two representative varieties of permanent magnet, neodymium generally offers greater magnetic power per volume
than ferrite, thereby enabling the highest degree of miniaturization, thus, neodymium is best suited for small equipment
applications. Figure 18 shows the relation between the size (volume) of a neodymium magnet and magnetic flux density.
The graph plots the correlation between the distance (L) from three versions of a 4mm x 4mm cross-section neodymium
magnet (1mm, 2mm, and 3mm thick) and magnetic flux density. Figure 19 shows Hall IC detection distance – a good guide
for determining the proper size and detection distance of the magnet. Based on the BU52075GWZ operating point max of
11.6mT, the minimum detection distance for the 1mm, 2mm and 3mm magnets would be 5.5mm, 6.8mm, and 7.7mm,
respectively. To increase the magnet’s detection distance, either increases the magnet’s thickness or sectional area.
15
t=1mm
12
t=3mm
9
6
5.5mm
t=2mm
6.8mm
3
7.7mm
0
0
2
4
6
8
10
12
14
16
18
20
Distance betw een Magnet and Hall IC [mm]
Figure 18. Magnetic Flux Density vs Distance between Magnet and Hall IC
X
Y
t
Magnet
Magnet Material: NEOMAX-44H (Material)
Maker: NEOMAX CO.,LTD.
Fig.2 ^X=Y=4mm
t
Fig.2
BU520t=1mm,2mm,3mm
L:BVUa5ri2a0b1le1
FigM.2agnet Size ^{11HFV Fig.}
BU52
2
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Fig.
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TSZ02201-0M2M0F414030-1-2
17.Oct.2014 Rev.001
op,Br
L
201