A1125EUA-T Allegro Microsystems Inc, A1125EUA-T Datasheet - Page 5

• Manufacturer Part Number: A1125EUA-T
• Description: CHOPPER STABILIZED PRECISION HALL SWITCH
• Manufacturer: Allegro Microsystems Inc
• Type: Unipolar Switchr

Specifications of A1125EUA-T

• Sensing Range: 50G Trip, 5G Release
• Voltage - Supply: 3 V ~ 24 V
• Current - Supply: 4mA
• Current - Output (max): 60mA
• Output Type: Digital, Open Collector
• Features: High Temperature
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 3-SIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A1120 and
A1125
Operation
The output of the A1120 devices switches low (turns on) when
a magnetic field perpendicular to the Hall element exceeds the
operate point threshold, B
magnetic field is reduced below the release point, B
output goes high (turns off). The output of the A1125 devices
switches high (turns off) when a magnetic field perpendicular to
the Hall element exceeds the operate point threshold, B
panel B of figure 1). When the magnetic field is reduced below
the release point, B
sistor is capable of sinking current up to the short circuit current
limit, I
The difference in the magnetic operate and release points is the
hysteresis, B
clean switching of the output even in the presence of external
mechanical vibration and electrical noise. Powering-on the device
in the hysteresis range (less than B
Figure 1. Device switching behavior. In panels A and B, on the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength.
This behavior can be exhibited when using an electrical circuit such as that shown in panel C.
After turn-on, the output voltage is V
V+
0
0
OM
, which is a minimum of 30 mA.
HYS ,
B
(A)
HYS
of the device. This built-in hysteresis allows
RP
, the device output goes low (turns on).
OP
(see panel A of figure 1). When the
B+
V
V
Chopper Stabilized Precision Hall Effect Switches
OP
CC
OUT(SAT)
OUT(SAT)
and higher than B
. The output tran-
V+
0
0
Functional Description
RP
, the device
OP
RP
) will
(see
B
(B)
HYS
give an indeterminate output state. The correct state is attained
after the first excursion beyond B
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 external noise in the
application. As is shown in panel B of figure 1, a 0.1 μF capacitor
is typical.
Extensive applications information for Hall effect devicers is
available in:
• Hall-Effect IC Applications Guide, Application Note 27701
• Guidelines for Designing Subassemblies Using Hall-Effect
Devices, Application Note 27703.1
• Soldering Methods for Allegro’s Products – SMT and Through-
Hole, Application Note 26009
All are provided in Allegro Electronic Data Book, AMS-702, and
the Allegro Web site, www.allegromicro.com.
B+
V
V
CC
OUT(SAT)
V
S
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
C
0.1 μF
BYP
OP
or B
A1120
A1125
RP
VCC
GND
.
(C)
VOUT
Output
R
L
5