BU52001GUL_10 Datasheet, PDF (13/20 Pages) Rohm – Omnipolar Detection Hall ICs

BU52001GUL,BU52011HFV,BU52021HFV,
BU52015GUL,BU52025G,BU52051NVX, BD7411G
(Magnetic Field Detection Mechanism)
Technical Note
S
N
S
S
N
S
N
Flux
Flux
Fig.36
The Hall IC cannot detect magnetic fields that run horizontal to the package top layer.
Be certain to configure the Hall IC so that the magnetic field is perpendicular to the top layer.
S
S
N
High
Flux
OUT [V]
High
N
N
S
Flux
High
Low
Low
Bop N Brp N
N-Pole
B
0
Brp S Bop S
Magnetic flux density [mT]
S-Pole
Fig.37
The Omnipolar detection Hall IC detects magnetic fields running perpendicular to the top surface of the package. There is
an inverse relationship between magnetic flux density and the distance separating the magnet and the Hall IC: when
distance increases magnetic density falls. When it drops below the operate point (Bop), output goes HIGH. When the
magnet gets closer to the IC and magnetic density rises, to the operate point, the output switches LOW. In LOW output
mode, the distance from the magnet to the IC increases again until the magnetic density falls to a point just below Bop, and
output returns HIGH. (This point, where magnetic flux density restores HIGH output, is known as the release point, Brp.)
This detection and adjustment mechanism is designed to prevent noise, oscillation and other erratic system operation.
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13/19
2010.01 - Rev.C