NOTE: For detailed information on purchasing options, contact your
local Allegro field applications engineer or sales representative.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan
for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The
information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-
sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
Recommended Substitutions:
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
A1140, A1142, and A1143
For existing customer transition, and for new customers or new appli-
cations, refer to the following parts:
• For the A1140ELHLT-T use the A1150LLHLX-T
• For the A1142ELHLT-T use the A1152LLHLX-T
• For the A1142LUA-T use the A1152LUA-T
• For the A1143EUA-T use the A1153LUA-T
• For the A1143LUA-T use the A1153LUA-T
• For the A1143ELHLT-T use the A1153LLHLX-T
• For the A1143LLHLT-T use the A1153LLHLX-T
Date of status change: October 31, 2011
This device is no longer in production. The device should not be
purchased for new design applications. Samples are no longer available.
Discontinued Product
Description
The A1140, A1142, and A1143 devices are sensitive, two-wire,
unipolar, Hall effect switches that are factory-programmed at
end-of-line to optimize magnetic switchpoint accuracy. These
devices use a patented high frequency chopper-stabilization
technique, produced using the Allegro advanced BiCMOS
wafer fabrication process, to achieve magnetic stability and
to eliminate offset inherent in single-element devices exposed
to harsh application environments.
Commonly found in a number of automotive applications,
these switches are utilized in sensing seat track position,
seat belt buckle presence, hood/trunk latching, and shift
selector position. Two-wire unipolar switches, such as the
A1140/A1142/A1143 family, are particularly advantageous in
price-sensitive applications because they require one less wire
for operation than do switches with the more traditional open-
collector output. Additionally, the system designer inherently
gains diagnostics because there is always output current flowing,
which should be in either of two narrow ranges. Any current
level not within these ranges indicates a fault condition. The
A1140/A1142/A1143 family of switches also features on-chip
A1140-DS, Rev. 17
Features and Benefits
▪ Chopper stabilization
▫ Low switchpoint drift over operating
temperature range
▫ Low sensitivity to stress
▪ Factory programmed at end-of-line for optimized
switchpoints
▪ On-chip protection
▫ Supply transient protection
▫ Reverse-battery protection
▫ On-board voltage regulator
▫ 3.5 to 24 V operation
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
Continued on the next page…
Functional Block Diagram
Not to scale
Packages: 3 pin SOT23W (suffix LH), and
3 pin SIP (suffix UA)
A1 140, A1142, and A1 143
Amp
Regulator
Low-Pass
Filter
GND
VCC
GND
Package UA Only
0.01 uF
V+
Clock/Logic
Dynamic Offset
Cancellation
Sample and Hold
To All Subcircuits
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
2
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
transient protection and a Zener clamp to protect against overvoltage
conditions on the supply line.
The output currents of the A1143 switch HIGH in the presence of a
south (+) polarity magnetic field of sufficient strength, and switch
LOW otherwise, as in the presence of a weak field or a north (–)
polarity field. The other two devices in the family (A1140 and
A1142) have an opposite output: the currents switch LOW in the
presence of a south-polarity magnetic field of sufficient strength,
and switch HIGH otherwise. The other differences in the switches
are their defined low current levels and magnetic switchpoints.
All versions are offered in two package styles. The LH is a SOT-
23W, miniature low-profile package for surface-mount applications.
The UA is a three-lead ultramini SIP for through-hole mounting.
Each package is available in a lead (Pb) free version (suffix, –T)
with 100% matte tin plated leadframe. Field-programmable versions
also available: A1180, A1182, and A1183.
Absolute Maximum Ratings
Characteristic Symbol Notes Rating Units
Supply Voltage VCC 28 V
Reverse Supply Voltage VRCC –18 V
Magnetic Flux Density B Unlimited G
Operating Ambient Temperature TA
Range E –40 to 85 ºC
Range L –40 to 150 ºC
Maximum Junction Temperature TJ(max) 165 ºC
Storage Temperature Tstg –65 to 170 ºC
Description (continued)
NC
1
2
3
1. VCC
2. No connection
3. GND
123
1. VCC
2. GND
3. GND
Package LH, 3-pin SOT Package UA, 3-pin SIP
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Product Selection Guide
Part Number Packing1Package Operating Ambient
Temperature, TA
(°C)
Output Level in
South (+) Field2
Supply Current at
Low Output, ICC(L)
(mA)
A1140ELHLT-T3,4 Tape and Reel, 3000 pieces/reel Surface Mount –40 to 85 Low 2 to 5
A1142ELHLT-T5Tape and Reel, 3000 pieces/reel Surface Mount –40 to 85 Low
5 to 6.9
A1142LUA-T5Bulk Bag, 500 pieces/bag Through Hole –40 to 150
A1143ELHLT-T5Tape and Reel, 3000 pieces/reel Surface Mount –40 to 85
High
A1143EUA-T5Bulk Bag, 500 pieces/bag Through Hole
A1143LLHLT-T5Tape and Reel, 3000 pieces/reel Surface Mount –40 to 150
A1143LUA-T5Bulk Bag, 500 pieces/bag Through Hole
1Contact Allegro for additional packing options.
2South (+) magnetic fields must be of sufficient strength.
3This device is available only in limited distribution. Interested customers should contact the appropriate sales person or field application
engineer for more information on availability.
4Variant is in production but has been determined to be NOT FOR NEW DESIGN. This classification indicates that sale of the variant is cur-
rently restricted to existing customer applications. The variant should not be purchased for new design applications because obsolescence
in the near future is probable. Samples are no longer available. Status change: January 31, 2011.
5These variants are in production, however, they have been deemed Pre-End of Life. The products are approaching end of life. Within a
minimum of 6 months, the devices will enter their final, Last Time Buy, order phase. Suggested replacements: for the A1142ELHLT-T use
the A1152LLHLX-T, for the A1143ELHLT-T and the A1143LLHLT-T use the A1153LLHLX-T. Status change: January 31, 2011. Suggested
replacements: for the A1142LUA-T use the A1152LUA-T, for the A1143EUA-T and the A1143LUA-T use the A1153LUA-T. Status change:
March 8, 2011.
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
4
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ELECTRICAL CHARACTERISTICS over the operating voltage and temperature ranges, unless otherwise specified
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage1VCC 3.5 – 24 V
Supply Current2
ICC(L)
B>BOP for A1140 2 – 5 mA
B>BOP for A1142; B<BRP for A1143 5 -– 6.9 mA
ICC(H)
B>BOP for A1143
B<BRP for A1140, A1142 12 -– 17 mA
Reverse Supply Current IRCC VRCC = –18 V – – –1.6 mA
Supply Zener Clamp Voltage VZSUPPLY ICC = ICC(L)(max) + 3 mA; TA = 25°C 28 – 40 V
Supply Zener Clamp Current IZSUPPLY VZSUPPLY = 28 V – – ICC(L)(max)
+ 3 mA mA
Output Slew Rate3di/dt Capacitance of the oscilloscope performing the
measurement = 20 pF – 36 – mA/s
Chopping Frequency fC– 200 – kHz
Power-On Time3ton CBYPASS = 0.01 F––25s
Power-On State5,6 POS t < ton; VCC slew rate > 25 mV/s– HIGH – –
1VCC represents the generated voltage between the VCC pin and the GND pin.
2Relative values of B use the algebraic convention, where positive values indicate south magnetic polarity, and negative values indicate north magnetic
polarity; therefore greater B values indicate a stronger south polarity field (or a weaker north polarity field, if present).
3Measured without bypass capacitor between VCC and GND. Use of a bypass capacitor results in slower current change.
3Measured with and without bypass capacitor of 0.01 F. Adding a larger bypass capacitor causes longer Power-On Time.
5POS is defined as true only with a VCC slew rate of 25 mV / s or greater. Operation with a VCC slew rate less than 25 mV / s can permanently harm
device performance.
6POS is undefined for t > ton or BRP < B < BOP .
MAGNETIC CHARACTERISTICS over the operating voltage and temperature ranges, unless otherwise specified
Characteristic Symbol Test Conditions Min. Typ.* Max. Units
Operate Point BOP
A1140, A1142 ICC = ICC(L) 50 80 110 G
A1143 ICC = ICC(H)
Release Point BRP
A1140, A1142 ICC = ICC(H) 45 65 105 G
A1143 ICC = ICC(L)
Hysteresis BHYS BHYS = BOP – BRP 51530G
*Typical data are for initial design estimations only, and assume optimum manufacturing and application conditions, such as TA = 25°C and VCC = 12 V.
Performance may vary for individual units, within the specified maximum and minimum limits.
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
5
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Characteristic Data
0
2
6
8
10
Supply Current (Low) versus Ambient Temperature
at Various Levels of VCC
(A1142 and A1143)
Supply Current (Low) versus Ambient Temperature
at Various Levels of VCC
(A1140)
Ambient Temperature, TA (°C)
Ambient Temperature, TA (°C)
VCC
3.5 V
12.0 V
24.0 V
VCC
3.5 V
12.0 V
24.0 V
ICC(L) (mA)
ICC(L) (mA)
0
2
6
8
10
4 4
–50
0
50
100
150
200
–50
0
50
100
150
200
–50
0
50
100
150
200
Operate Point versus Ambient Temperature
at Various Levels of VCC
(A1140, A1142, and A1143)
Supply Current (High) versus Ambient Temperature
at Various Levels of VCC
(A1140, A1142, and A1143)
Ambient Temperature, TA (°C)
Ambient Temperature, TA (°C)
VCC
3.5 V
12.0 V
24.0 V
VCC
3.5 V
12.0 V
24.0 V
ICC(H) (mA)
BOP (G)
10
12
16
18
20
14
–50
0
50
100
150
200
Switchpoint Hysteresis versus Ambient Temperature
at Various Levels of VCC
(A1140, A1142, and A1143)
Ambient Temperature, TA (°C)
VCC
3.5 V
12.0 V
24.0 V
BHYS (G)
0
2
6
8
10
4
–50
0
50
100
150
200
50
60
80
90
110
100
70
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
6
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information
Characteristic Symbol Test Conditions* Value Units
Package Thermal Resistance RθJA
Package LH, 1-layer PCB with copper limited to solder pads 228 ºC/W
Package LH, 2-layer PCB with 0.463 in.2 of copper area each side
connected by thermal vias 110 ºC/W
Package UA, 1-layer PCB with copper limited to solder pads 165 ºC/W
*Additional thermal information available on Allegro Web site.
6
7
8
9
2
3
4
5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
20 40 60 80 100 120 140 160 180
Temperature (ºC)
Maximum Allowable VCC (V)
Power Derating Curve
(RθJA = 228 ºC/W)
1-layer PCB, Package LH
(RθJA = 110 ºC/W)
2-layer PCB, Package LH
(RθJA = 165 ºC/W)
1-layer PCB, Package UA
VCC(min)
VCC(max)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
20 40 60 80 100 120 140 160 180
Temperature (°C)
Power Dissipation, P
D
(mW)
Power Dissipation versus Ambient Temperature
(R
θJA
= 165 ºC/W)
1-layer PCB, Package UA
(RθJA = 228 ºC/W)
1-layer PCB, Package LH
(RθJA = 110 ºC/W)
2-layer PCB, Package LH
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
7
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Functional Description
B
OP
B
RP
B
HYS
I
CC(H)
I
CC
I
CC(L)
Switch to Low
Switch to High
B+
B–
I+
0
(A) A1140, A1142
B
OP
B
RP
B
HYS
I
CC(H)
I
CC
I
CC(L)
Switch to High
Switch to Low
B+
I+
B–
0
(B) A1143
Operation
The output, ICC, of the A1140 and A1142 devices switch low
after the magnetic field at the Hall element exceeds the oper-
ate point threshold, BOP. When the magnetic field is reduced to
below the release point threshold, BRP, the device output goes
high. The differences between the magnetic operate and release
point is called the hysteresis of the device, BHYS. This built-in
hysteresis allows clean switching of the output even in the pres-
ence of external mechanical vibration and electrical noise. The
A1143 device switches with opposite polarity for similar BOP
and BRP values, in comparison to the A1140 and A1142 (see
figure 1).
Figure 1. Alternative switching behaviors are available in the A114x device family. On the horizontal axis, the B+ direction indicates
increasing south polarity magnetic field strength, and the B– direction indicates decreasing south polarity field strength (including the
case of increasing north polarity).
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
8
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Chopper Stabilization Technique
When using Hall-effect technology, a limiting factor for
switchpoint accuracy is the small signal voltage developed
across the Hall element. This voltage is disproportionally small
relative to the offset that can be produced at the output of the
Hall element. This makes it difficult to process the signal while
maintaining an accurate, reliable output over the specified oper-
ating temperature and voltage ranges.
Chopper stabilization is a unique approach used to minimize
Hall offset on the chip. The patented Allegro technique, namely
Dynamic Quadrature Offset Cancellation, removes key sources
of the output drift induced by thermal and mechanical stresses.
This offset reduction technique is based on a signal modulation-
demodulation process. The undesired offset signal is separated
from the magnetic field-induced signal in the frequency domain,
through modulation. The subsequent demodulation acts as a
modulation process for the offset, causing the magnetic field-
induced signal to recover its original spectrum at baseband, while
the DC offset becomes a high-frequency signal. The magnetic-
sourced signal then can pass through a low-pass filter, while
the modulated DC offset is suppressed. This configuration is
illustrated in figure 2.
The chopper stabilization technique uses a 200 kHz high
frequency clock. For demodulation process, a sample and hold
technique is used, where the sampling is performed at twice the
chopper frequency (400 kHz). This high-frequency operation
allows a greater sampling rate, which results in higher accuracy
and faster signal-processing capability. This approach desensi-
tizes the chip to the effects of thermal and mechanical stresses,
and produces devices that have extremely stable quiescent Hall
output voltages and precise recoverability after temperature
cycling. This technique is made possible through the use of a
BiCMOS process, which allows the use of low-offset, low-noise
amplifiers in combination with high-density logic integration
and sample-and-hold circuits.
The repeatability of magnetic field-induced switching is affected
slightly by a chopper technique. However, the Allegro high-
frequency chopping approach minimizes the affect of jitter and
makes it imperceptible in most applications. Applications that
are more likely to be sensitive to such degradation are those
requiring precise sensing of alternating magnetic fields; for
example, speed sensing of ring-magnet targets. For such applica-
tions, Allegro recommends its digital device families with lower
sensitivity to jitter. For more information on those devices,
contact your Allegro sales representative.
Figure 2. Chopper stabilization circuit (Dynamic Quadrature Offset Cancellation)
Amp
Regulator
Clock/Logic
Hall Element
Sample and
Hold
Low-Pass
Filter
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
9
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Application Information
For additional general application information, visit the Allegro
Web site at www. allegromicro.com.
GND
A114x
VCC
V+
0.01 F
A
B
B
GND
ECU
Package UA Only
A
BMaximum separation 5 mm
RSENSE
CBYP
Figure 3. Typical application circuit
Typical Application Circuit
The A114x family of devices must be protected by an external
bypass capacitor, CBYP, connected between the supply, VCC,
and the ground, GND, of the device. CBYP reduces both external
noise and the noise generated by the chopper-stabilization func-
tion. As shown in figure 3, a 0.01 μF capacitor is typical.
Installation of CBYP must ensure that the traces that connect it to
the A114x pins are no greater than 5 mm in length.
All high-frequency interferences conducted along the supply
lines are passed directly to the load through CBYP, and it serves
only to protect the A114x internal circuitry. As a result, the load
ECU (electronic control unit) must have sufficient protection,
other than CBYP, installed in parallel with the A114x.
A series resistor on the supply side, RS (not shown), in combina-
tion with CBYP, creates a filter for EMI pulses.
When determining the minimum VCC requirement of the A114x
device, the voltage drops across RS and the ECU sense resistor,
RSENSE, must be taken into consideration. The typical value for
RSENSE is approximately 100 Ω.
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
10
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Power Derating
The device must be operated below the maximum junction
temperature of the device, TJ(max). Under certain combinations of
peak conditions, reliable operation may require derating sup-
plied power or improving the heat dissipation properties of the
application. This section presents a procedure for correlating
factors affecting operating TJ. (Thermal data is also available on
the Allegro MicroSystems Web site.)
The Package Thermal Resistance, RJA, is a figure of merit sum-
marizing the ability of the application and the device to dissipate
heat from the junction (die), through all paths to the ambient air.
Its primary component is the Effective Thermal Conductivity,
K, of the printed circuit board, including adjacent devices and
traces. Radiation from the die through the device case, RJC, is
relatively small component of RJA. Ambient air temperature,
TA, and air motion are significant external factors, damped by
overmolding.
The effect of varying power levels (Power Dissipation, PD), can
be estimated. The following formulas represent the fundamental
relationships used to estimate TJ, at PD.
PD = VIN × IIN (1)
T = PD × RJA (2)
TJ = TA + ΔT (3)
For example, given common conditions such as: TA= 25°C,
VCC = 12 V, ICC = 4 mA, and RJA = 140 °C/W, then:
P
D = VCC × ICC = 12 V × 4 mA = 48 mW
T = PD × RJA = 48 mW × 140 °C/W = 7°C
T
J = TA + T = 25°C + 7°C = 32°C
A worst-case estimate, PD(max), represents the maximum allow-
able power level (VCC(max), ICC(max)), without exceeding TJ(max),
at a selected RJA and TA.
Example: Reliability for VCC at TA =
150°C, package UA, using
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
RJA
=
165°C/W, TJ(max) =
165°C, VCC(max)
= 24 V, and
ICC(max) = 17 mA.
Calculate the maximum allowable power level, PD(max). First,
invert equation 3:
Tmax = TJ(max) – TA = 165
°C
–
150
°C = 15
°C
This provides the allowable increase to TJ resulting from internal
power dissipation. Then, invert equation 2:
PD(max) = Tmax ÷ RJA = 15°C ÷ 165 °C/W = 91 mW
Finally, invert equation 1 with respect to voltage:
VCC(est) = PD(max) ÷ ICC(max) = 91 mW ÷ 17 mA = 5 V
The result indicates that, at TA, the application and device can
dissipate adequate amounts of heat at voltages ≤VCC(est).
Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reli-
able operation between VCC(est) and VCC(max) requires enhanced
RJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and
VCC(max) is reliable under these conditions.
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
11
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Device Qualification Program
EMC (Electromagnetic Compatibility) Requirements
Test Name Reference Specification
ESD – Human Body Model AEC-Q100-002
ESD – Machine Model AEC-Q100-003
Conducted Transients ISO 7637-2
Direct RF Injection ISO 11452-7
Bulk Current Injection ISO 11452-4
TEM Cell ISO 11452-3
Contact Allegro for information.
Contact your local representative for EMC results.
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
12
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package LH, 3-Pin; (SOT-23W)
0.55 REF
Gauge Plane
Seating Plane
0.25 BSC
0.95 BSC
0.95
1.00
0.70 2.40
2
1
AActive Area Depth, 0.28 mm REF
B
C
C
B
Reference land pattern layout
All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances
Branding scale and appearance at supplier discretion
A
PCB Layout Reference View
Standard Branding Reference View
1
Branded Face
N = Last two digits of device part number
T = Temperature code
NNT
2.90 +0.10
–0.20
4°±4°
8X 10° REF
0.180+0.020
–0.053
0.05 +0.10
–0.05
0.25 MIN
1.91 +0.19
–0.06
2.98 +0.12
–0.08
1.00 ±0.13
0.40 ±0.10
For Reference Only; not for tooling use (reference dwg. 802840)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
DHall element, not to scale
D
D
D
1.49
0.96
3
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
13
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Package UA, 3-Pin SIP
231
0.79 REF
1.27 NOM
2.16
MAX
0.51
REF
45°
C
45°
B
E
E
E
2.04
1.44
Gate burr area
A
B
C
Dambar removal protrusion (6X)
A
D
E
D
Branding scale and appearance at supplier discretion
Hall element, not to scale
Active Area Depth, 0.50 mm REF
For Reference Only; not for tooling use (reference DWG-9049)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
Standard Branding Reference View
= Supplier emblem
N = Last two digits of device part number
T = Temperature code
NNT
1
Mold Ejector
Pin Indent
Branded
Face
4.09 +0.08
–0.05
0.41 +0.03
–0.06
3.02 +0.08
–0.05
0.43 +0.05
–0.07
15.75 ±0.51
1.52 ±0.05
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Ef fect Switches
A1 140, A1 142, and
A1143
14
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Copyright ©2004-2010, Allegro MicroSystems, Inc.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per-
mit improvements in the per for mance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the
information being relied upon is current.
Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the
failure of that life support device or system, or to affect the safety or effectiveness of that device or system.
The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil i ty for its use;
nor for any in fringe ment of patents or other rights of third parties which may result from its use.
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Revision History
Revision Revision Date Description of Revision
Rev. 17 March 8, 2011 Change in product availability
