A1140, A1141, A1142, and A1143
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
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
Description
The A1140, A1141, 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 to sense seat track position,
seat belt buckle presence, hood/trunk latching, and shift
selector position. Two-wire unipolar switches, such as the
A1140/41/42/43 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 A1140/41/42/43 family of switches also
Packages: 3 pin SOT23W (suffix LH), and
3 pin SIP (suffix UA)
Continued on the next page…
Not to scale
Functional Block Diagram
V+
VCC
Regulator
To All Subcircuits
0.01 uF
Dynamic Offset
Cancellation
Clock/Logic
Sample and Hold
Low-Pass
Filter
Amp
GND
Package UA Only
GND
A1140-DS, Rev. 8
A1140, A1141,
A1142, and A1143
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
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, A1181, A1182, and A1183.
Description (continued)
features on-chip transient protection and a Zener clamp to protect
against overvoltage conditions on the supply line.
The output currents of the A1141 and 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,
Absolute Maximum Ratings
Characteristic
Supply Voltage
Reverse Supply Voltage
Magnetic Flux Density
Operating Ambient Temperature
Maximum Junction Temperature
Storage Temperature
Symbol
V
CC
V
RCC
B
T
A
T
J
(max)
T
stg
Range E
Range L
Notes
Rating
28
–18
Unlimited
–40 to 85
–40 to 150
165
–65 to 170
Units
V
V
G
ºC
ºC
ºC
ºC
Package LH, 3-pin SOT
Package UA, 3-pin SIP
3
NC
1. VCC
2. No connection
3. GND
1
2
1. VCC
2. GND
3. GND
1
2
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
2
A1140, A1141,
A1142, and A1143
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
Product Selection Guide
Part Number
A1140EUATI-T
4
A1140LUATI-T
4
A1141EUATI-T
4
A1141LUATI-T
4
A1142ELHLT-T
A1142EUA-T
A1142EUATI-T
4
A1142LLHLT-T
A1142LUA-T
A1142LUATI-T
4
A1143ELHLT-T
A1143EUA-T
A1143EUATI-T
4
A1143LLHLT-T
A1143LUA-T
A1143LUATI-T
4
1
Pb-based
Pb-Free
1
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Packing
2
Tape and Reel, 2000 pieces/reel
Tape and Reel, 2000 pieces/reel
Tape and Reel, 2000 pieces/reel
Tape and Reel, 2000 pieces/reel
Tape and Reel, 3000 pieces/reel
Bulk Bag, 500 pieces/bag
Tape and Reel, 2000 pieces/reel
Tape and Reel, 3000 pieces/reel
Bulk Bag, 500 pieces/bag
Tape and Reel, 2000 pieces/reel
Tape and Reel, 3000 pieces/reel
Bulk Bag, 500 pieces/bag
Tape and Reel, 2000 pieces/reel
Tape and Reel, 3000 pieces/reel
Bulk Bag, 500 pieces/bag
Package
Through Hole
Through Hole
Through Hole
Through Hole
Surface Mount
Through Hole
Surface Mount
Through Hole
Surface Mount
Through Hole
Surface Mount
Through Hole
Operating Ambient
Temperature, T
A
(°C)
–40 to 85
–40 to 150
–40 to 85
–40 to 150
–40 to 85
Output Level in
South (+) Field
3
Low
Supply Current at
Low Output, I
CC(L)
(mA)
2 to 5
High
Low
–40 to 150
5 to 6.9
–40 to 85
High
–40 to 150
Yes
Tape and Reel, 2000 pieces/reel
variants are being phased out of the product line.
(a) Certain variants cited in this footnote are in production but have been determined to be NOT FOR NEW DESIGN. This classification indicates that
sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because
obsolescence in the near future is probable. Samples are no longer available. Status change: May 1, 2006. These variants include A1140EUATI,
A1140LUATI, A1140LUATI, A1141EUA, A1141EUATI, A1141LLHLT, A1141LUA, A1141LUATI, A1142EUATI, A1142LUATI,A1142LLHLT, A1142LUA,
A1143EUATI, A1143LUA , and A1143LUATI.
(b) Certain variants cited in this footnote are in production but have been determined to be LAST TIME BUY. This classification indicates that the
product is obsolete and notice has been given. Sale of this device is currently restricted to existing customer applications. The device should not be
purchased for new design applications because of obsolescence in the near future. Samples are no longer available. Status date change October 31,
2006. Deadline for receipt of LAST TIME BUY orders is April 27, 2007. These variants include: A1142ELHLT, A1142EUA, A1143ELHLT, A1143EUA, and
A1143LLHLT.
2
Contact Allegro for additional packing options.
3
South (+) magnetic fields must be of sufficient strength.
4
Some restrictions may apply to certain types of sales. Contact Allegro for details.
5
The sensors listed in this footnote are available only in limited distribution. Interested customers should contact the appropriate sales person or
field application engineer for more information on availability. These variants include: A1140ELHLT-T, A1140EUA-T, A1140LLHLT-T, A1140LUA-T,
A1141ELHLT-T, A1141EUA-T, A1141LLHLT-T, and A1141LUA-T.
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
3
A1140, A1141,
A1142, and A1143
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
Symbol
V
CC
I
CC(L)
B>B
OP
for A1140; B<B
RP
for A1141
B>B
OP
for A1142; B<B
RP
for A1143
B>B
OP
for A1141, A1143
B<B
RP
for A1140, A1142
V
RCC
= –18 V
I
CC
= I
CC(L)(max)
+ 3 mA; T
A
= 25°C
V
ZSUPPLY
= 28 V
Capacitance of the oscilloscope performing the
measurement = 20 pF
Test Conditions
Min.
3.5
2
5
12
–
28
–
–
–
C
BYPASS
= 0.01
μF
ELECTRICAL CHARACTERISTICS
over the operating voltage and temperature ranges, unless otherwise specified
Characteristic
Supply Voltage
1
Typ.
–
–
-–
-–
–
–
–
36
200
–
HIGH
Max.
24
5
6.9
17
–1.6
40
I
CC(L)(max)
+ 3 mA
–
–
25
–
Units
V
mA
mA
mA
mA
V
mA
mA/μs
kHz
μs
–
Supply Current
2
I
CC(H)
Reverse Supply Current
Supply Zener Clamp Voltage
Supply Zener Clamp Current
Output Slew Rate
3
Chopping Frequency
Power-On Time
3
Power-On State
5,6
1
V
CC
represents
2
Relative values
I
RCC
V
ZSUPPLY
I
ZSUPPLY
di/dt
f
C
t
on
POS
–
–
t < t
on
;
V
CC
slew rate > 25 mV/μs
the generated voltage between the VCC pin and the GND pin.
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).
3
Measured without bypass capacitor between VCC and GND. Use of a bypass capacitor results in slower current change.
3
Measured with and without bypass capacitor of 0.01
μF.
Adding a larger bypass capacitor causes longer Power-On Time.
5
POS is defined as true only with a V
CC
slew rate of 25 mV /
μs
or greater. Operation with a V
CC
slew rate less than 25 mV /
μs
can permanently harm
device performance.
6
POS is undefined for t > t or B
on
RP
< B < B
OP
.
MAGNETIC CHARACTERISTICS
over the operating voltage and temperature ranges, unless otherwise specified
Characteristic
Operate Point
Symbol
B
OP
Test Conditions
A1140, A1142 I
CC
= I
CC(L)
A1141, A1143 I
CC
= I
CC(H)
A1140, A1142 I
CC
= I
CC(H)
A1141, A1143 I
CC
= I
CC(L)
B
HYS
= B
OP
– B
RP
Min.
50
Typ.*
80
Max.
110
Units
G
Release Point
Hysteresis
B
RP
B
HYS
45
5
65
15
105
30
G
G
*Typical data are for initial design estimations only, and assume optimum manufacturing and application conditions, such as T
A
= 25°C and V
CC
= 12 V.
Performance may vary for individual units, within the specified maximum and minimum limits.
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
4
A1140, A1141,
A1142, and A1143
Sensitive Two-Wire Chopper-Stabilized
Unipolar Hall Effect Switches
Characteristic Data
Supply Current (Low) versus Ambient Temperature
at Various Levels of V
CC
(A1142 and A1143)
10
8
Supply Current (Low) versus Ambient Temperature
at Various Levels of V
CC
(A1140 and A1141)
10
8
V
CC
I
CC(L)
(mA)
3.5 V
12.0 V
24.0 V
I
CC(L)
(mA)
6
4
2
0
–50
6
4
2
0
–50
V
CC
3.5 V
12.0 V
24.0 V
0
50
100
150
200
0
50
100
150
200
Ambient Temperature, T
A
(°C)
Ambient Temperature, T
A
(°C)
Supply Current (High) versus Ambient Temperature
at Various Levels of V
CC
(A1140, A1141, A1142, and A1143)
20
18
V
CC
I
CC(H)
(mA)
16
14
12
10
–50
3.5 V
12.0 V
24.0 V
0
50
100
150
200
Ambient Temperature, T
A
(°C)
Operate Point versus Ambient Temperature
at Various Levels of V
CC
(A1140, A1141, A1142, and A1143)
110
100
90
Switchpoint Hysteresis versus Ambient Temperature
at Various Levels of V
CC
(A1140, A1141, A1142, and A1143)
10
8
V
CC
B
HYS
(G)
3.5 V
12.0 V
24.0 V
6
4
2
0
–50
V
CC
3.5 V
12.0 V
24.0 V
B
OP
(G)
80
70
60
50
–50
0
50
100
150
200
0
50
100
150
200
Ambient Temperature, T
A
(°C)
Ambient Temperature, T
A
(°C)
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
5
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