3422 Datasheet, PDF (7/10 Pages) Unisonic Technologies – HIGH PERFORMANCE DUAL BIPOLAR OPERATINAL AMPLIFIER

3422
HALL-EFFECT,
DIRECTION-DETECTION
SENSOR
Applications Information
Operation with Fine-Pitch Ring Magnets. For
targets with a circular pitch of less than 4 mm, a
performance improvement can be observed by rotat-
ing the front face of the sensor subassembly (see
below). This sensor rotation decreases the effective
sensor-to-sensor spacing, provided that the Hall
elements are not rotated beyond the width of the
target.
Applications. It is strongly recommended that an
external 0.01 µF bypass capacitor be connected (in
close proximity to the Hall sensor) between the
supply and ground of the device to reduce both
external noise and noise generated by the internal
logic.
The simplest form of magnet that will operate
these devices is a ring magnet. Other methods of
operation, such as linear magnets, are possible.
Extensive applications information on magnets and
Hall-effect sensors is also available in the “Hall-
Effect IC Applications Guide” which can be found in
the latest issue of Application Note 27701, at
www.allegromicro.com/techpub2/an/an27701
0.059"
1.50 mm
A
1
2
3
4
5
α
TARGET FACE WIDTH, F
>1.50 SIN α (mm)
>0.059 SIN α (inch)
A
1
2
3
4
5
Rotated Sensor for
Fine-Pitch Ring
Magnets
Dwg. MH-024
www.allegromicro.com
7