BU52058GWZ Datasheet, PDF (11/18 Pages) Rohm – Omnipolar Detection Hall IC

BU52058GWZ
Datasheet
●Operational Notes
1) Absolute maximum ratings
Exceeding the absolute maximum ratings for supply voltage, operating conditions, etc. may result in damage to or
destruction of the IC. Because the source (short mode or open mode) cannot be identified if the device is damaged in this
way, it is important to take physical safety measures such as fusing when implementing any special mode that operates in
excess of absolute rating limits.
2) GND voltage
Make sure that the GND terminal potential is maintained at the minimum in any operating state, and is always kept lower
than the potential of all other pins.
3) Thermal design
Use a thermal design that allows for sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
4) Pin shorts and mounting errors
Use caution when positioning the IC for mounting on printed circuit boards. Mounting errors, such as improper positioning
or orientation, may damage or destroy the device. The IC may also be damaged or destroyed if output pins are shorted
together, or if shorts occur between the output pin and supply pin or GND.
5) Positioning components in proximity to the Hall IC and magnet
Positioning magnetic components in close proximity to the Hall IC or magnet may alter the magnetic field, and therefore the
magnetic detection operation. Thus, placing magnetic components near the Hall IC and magnet should be avoided in the
design if possible. However, where there is no alternative to employing such a design, be sure to thoroughly test and
evaluate performance with the magnetic component(s) in place to verify normal operation before implementing the design.
6) Slide-by position sensing
Figure 21 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 22, 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, it can wind up switching output ON as the
magnet slides by in the process of position detection. Figure 23 plots magnetic flux density during the magnet slide-by.
Although a reverse magnetic field was generated in the process, the magnetic flux density decreased 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.
Magnet
Slide
d
L
Figure 21
Hall IC
Flux
A
S
N
Figure 22
B
Flux
10
8
6
4
2
0
-2
-4
-6
-8
-10
0
Reverse
1 2 3 4 5 6 7 8 9 10
Horizontal distance f rom the magnet [mm]
Figure 23
7) Operation in strong electromagnetic fields
Exercise extreme caution about using the device in the presence of a strong electromagnetic field, as such use may cause
the IC to malfunction.
8) Common impedance
Make sure that the power supply and GND wiring limits common impedance to the extent possible by, for example,
employing short, thick supply and ground lines. Also, take measures to minimize ripple such as using an inductor or
capacitor.
9) GND wiring pattern
When both a small-signal GND and high-current GND are provided, single-point grounding at the reference point of the set
PCB is recommended, in order to separate the small-signal and high-current patterns, and to ensure that voltage changes
due to the wiring resistance and high current do not cause any voltage fluctuation in the small-signal GND. In the same way,
care must also be taken to avoid wiring pattern fluctuations in the GND wiring pattern of external components.
10) Exposure to strong light
Exposure to halogen lamps, UV and other strong light sources may cause the IC to malfunction. If the IC is subject to such
exposure, provide a shield or take other measures to protect it from the light. In testing, exposure to white LED and
fluorescent light sources was shown to have no significant effect on the IC.
11) Power source design
Since the IC performs intermittent operation, it has peak current when it’s ON. Please taking that into account and under
examine adequate evaluations when designing the power source.
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TSZ22111・15・001
11/14
TSZ02201-0M3M0F413010-1-2
14.Feb.2013 Rev.001