A3212ELHLT-T Allegro, A3212ELHLT-T Datasheet - Page 8

• Manufacturer Part Number: A3212ELHLT-T
• Manufacturer: Allegro

A3211
A3212
Operation. The output of the A3212 switches low (turns on)
when a magnetic field perpendicular to the Hall sensor exceeds
the operate point B
output is capable of sinking up to 1 mA and the output voltage
is V
release point B
switches high (turns off). The dif fer ence in the magnetic operate
and release points is the hysteresis (B
built-in hysteresis allows clean switching of the output even
in the presence of external mechanical vibration and electrical
noise. The A3211 functions in the same manner, except the out-
put voltage is reversed from the A3212, as shown in the figures
to the right.
As used here, negative flux densities are defined as less than
zero (algebraic convention), i.e., -50 G is less than +10 G.
Applications. Allegro's pole-independent sensing technique
allows for operation with either a north pole or south pole mag-
net orientation, enhancing the manufacturability of the device.
The state-of-the-art technology provides the same output polarity
for either pole face.
be con nect ed (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 chopper-sta bi li za tion tech nique. This
is especially true due to the relatively high im ped ance of battery
supplies.
is a bar magnet with either pole near the branded surface of the
device. Many oth er meth ods of operation are possible. Ex ten -
sive applications information for Hall-effect sensors is available
in:
• Hall-Effect IC Applications Guide, Application Note 27701;
• Hall-Effect Devices: Soldering, Gluing, Potting, En cap su -
lat ing, and Lead Forming, Application Note 27703.1;
• Soldering of Through-Hole Hall-Sensor Dervices, Application
Note 27703; and
• Soldering of Surface-Mount Hall-Sensor Devices, Application
Note 27703.2.
All are provided at
OUT(ON)
It is strongly recommended that an external bypass ca pac i tor
The sim plest form of magnet that will op er ate these devices
and
. When the magnetic field is reduced below the
RPS
www.allegromicro.com
(or increased above B
OPS
(or is less than B
hys
OPN
) of the device. This
RPN
FUNCTIONAL DESCRIPTION (cont'd)
). After turn-on, the
), the device output
MAX
MAX
5 V
5 V
Micropower, Ultrasensitive
0
0
-B
-B
A3212
A3211
OUTPUT OFF
OUTPUT ON
X
B OPN
B OPN
Hall-Effect Switches
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
B
B RPN
RPN
MAGNETIC FLUX
MAGNETIC FLUX
OUTPUT OFF
OUTPUT ON
0
0
B RPS
B
RPS
0.1 ∝F
B
B OPS
OPS
OUTPUT ON
OUTPUT OFF
OUT P UT
S UP P LY
(3 V B AT T E R Y )
Dwg. E H-013-2
+B
+B
8