A3282ELHLT Allegro Microsystems Inc, A3282ELHLT Datasheet - Page 8

• Manufacturer Part Number: A3282ELHLT
• Description: IC SWITCH HALL EFFECT SOT23W
• Manufacturer: Allegro Microsystems Inc
• Type: Bipolar Latchr

Specifications of A3282ELHLT

• Sensing Range: 150G Trip, -150G Release
• Voltage - Supply: 3.6 V ~ 24 V
• Current - Supply: 3.5mA
• Current - Output (max): 25mA
• Output Type: Digital, Open Collector
• Features: Regulated Voltage
• Operating Temperature: -40°C ~ 85°C
• Package / Case: SOT-23W
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

A3282
Operation
The output of these devices switches low (turns on) when a
magnetic fi eld perpendicular to the Hall element exceeds the
operate point threshold, B
is V
up to the short circuit current limit, I
30 mA. Note that the device latches, that is, a south pole of suffi -
cient strength towards the branded surface of the device turns the
device on. The device remains on if the south pole is removed.
When the magnetic fi eld is reduced below the release point, B
the device output turns off (goes high). The difference in the
magnetic operate and release points is the hysteresis, B
the device. This built-in hysteresis allows clean switching of the
output even in the presence of external mechanical vibration and
electrical noise.
Powering-on the device in the hysteresis region (less than B
higher than B
state is attained after the fi rst excursion beyond B
Figure 1: Switching Behavior of Latches. In Panel A, on the horizontal axis, the B+ direction indicates increasing south polarity magnetic
fi eld strength, and the B– direction indicates decreasing south polarity fi eld strength (including the case of increasing north polarity). This
behavior can be exhibited when using a circuit such as that shown in panel B.
OUT(SAT)
. The output transistor is capable of sinking current
RP
) allows an indeterminate output state. The correct
V+
0
B–
OP
. After turn-on, the output voltage
(A)
B
HYS
0
OM
, which is a minimum of
B+
OP
Functional Description
or B
V
V
CC
OUT(SAT)
HYS
RP
.
OP
, of
Chopper-Stabilized Hall Effect Latch
and
RP
,
Applications
It is strongly recommended that an external bypass capacitor be
connected (in close proximity to the Hall element) between the
supply and ground of the device to reduce both external noise
and noise generated by the chopper stabilization technique. As is
shown in Panel B of fi gure 1, a 0.1μF capacitor is typical.
Extensive applications information on magnets and Hall-effect
devices is available in:
• Hall-Effect IC Applications Guide, AN27701,
• Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead
• Soldering Methods for Allegro’s Products – SMT and Through-
All are provided in Allegro Electronic Data Book, AMS-702 and
the Allegro Web site: www.allegromicro.com
Welding and Lead Forming, AN27703.1
Hole, AN26009
V
S
C
0.1 µF
BYP
A3282
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
(B)
VCC
GND
VOUT
R
LOAD
Output
7