Data Sheet

5
sensing.honeywell.com
Magnetoresistive Sensor ICs, Nanopower Series
Figure 2. Alignment of the Magnet to the Omnipolar Magnetoresistive Sensor IC
Ideal alignment: The magnet is aligned in the same plane as the sensor IC.
Offset alignment: The magnet is not aligned in the same plane as the sensor IC.
SM351LT,
SM353LT
Sensor IC
Magnet
Magnet movement
Magnet
SM351LT,
SM353LT
Sensor IC
Magnet movement
Magnet
Magnet
SM351LT,
SM353LT
Sensor IC
Magnet movement
end view
top view
ThesensorICdetectstheapproachingmagnet’shorizontalmagneticuxlines,turningthesensorICtoON.ThesensorICstaysONasthe
magnetcontinuestoapproach.WhenthemagnetislocateddirectlyoverthesensorIC,allmagneticuxlinesarenowhorizontal(seeFigure
2.C).(Note:ThisalignmentdecreasesthemagneticuxstrengthatthesensorIC.)
Themagneticuxlinesstayhorizontalasthemagnetapproachesthe
sensor IC (see Figure 2.A).
Deadzonesmayoccurwhenthemajorityofthemagnet’smagnetic
uxlinesbecomeverticalasitapproachesthesensorIC,turning
thesensorICtoON,thenOFF,thenON(seeFigure2.B).
Perpendicular magnet approach to the sensor IC eliminates possible dead zones.
Parallel magnet approach to the sensor IC may cause dead zones.
Figure 2.A
Figure 2.B
Figure 2.C