A1227LLTTR-T Allegro Microsystems Inc, A1227LLTTR-T Datasheet - Page 9

• Manufacturer Part Number: A1227LLTTR-T
• Description: HALL EFFECT LATCH FOR HIGH TEMPERATURE OPERATION
• Manufacturer: Allegro Microsystems Inc
• Type: Bipolar Latchr

Specifications of A1227LLTTR-T

• Sensing Range: 150G Trip, -150G Release
• Voltage - Supply: 3.8 V ~ 24 V
• Current - Supply: 6mA
• Current - Output (max): 25mA
• Output Type: Digital, Open Drain
• Features: Regulated Voltage
• Operating Temperature: -40°C ~ 150°C
• Package / Case: SOT-89-3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 620-1350-2

A1225, A1227
and
Switching Behavior
The output of the A1225, A1227, and A1229 devices switches
low (turns on) when a magnetic field perpendicular to the Hall
element exceeds the operate point threshold, B
After turn-on, the output is capable of sinking 25 mA and the
output voltage is V
a south pole of sufficient strength towards the branded surface
of the device turns the device on, and the device remains on with
removal of the south pole.
When the magnetic field is reduced below the release point, B
the device output goes high (turns off). The difference between
the magnetic operate point and release point is the hysteresis,
B
ing of the output, even in the presence of external mechanical
vibration and electrical noise.
When the device is powered-on in the hysteresis range, less than
B
output state is attained after the first excursion beyond B
B
Figure 1. Output switching characteristics
HYS
OP
RP
.
and higher than B
, of the device. This built-in hysteresis allows clean switch-
A1229
V+
0
B–
OUT(sat)
RP
, the device output goes high. The correct
B
. Notice that the device latches; that is,
HYS
Functional Description and Application Information
Hall Effect Latch for High Temperature Operation
B+
V
V
CC
OUT(sat)
OP
(see figure 1).
OP
or
RP
,
Application Information
The simplest form of magnet that will operate these devices is a
ring magnet, as shown in figure 2. Other methods of operation
are possible.
In three-wire applications the device output is connected through
a pull-up resistor to the supply pin or separate battery voltage
(figure 3). Switching of the output signal indicates sufficient
change of the magnetic field.
Figure 2. Typical magnetic target configuration using a ring magnet
Figure 3. Typical 3-wire application circuit
C
BYPASS
V+
VCC
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
A122x
GND
VOUT
V
PULLUP
R
PULLUP
Device
Output
C
(Optional)
L
9