The A3280--, A3281--, and A3283-- Hall-effect latches are ex-
tremely temperature-stable and stress-resistant sensors especially suited
for operation over extended temperature ranges to +150
C. Superior
high-temperature performance is made possible through dynamic offset
cancellation, which reduces the residual offset voltage normally caused
by device overmolding, temperature dependencies, and thermal stress.
The three devices are identical except for magnetic switch points.
Each device includes on a single silicon chip a voltage regulator,
Hall-voltage generator, small-signal amplifier, chopper stabilization,
Schmitt trigger, and a short-circuit protected open-collector output to
sink up to 25 mA. A south pole of sufficient strength will turn the
output on. A north pole is necessary to turn the output off. An on-board
regulator permits operation with supply voltages of 4.2 to 24 volts.
The first character of the part number suffix determines the device
operating temperature range; suffix `E' is for -40
C to +85
C and
`L' is -40
C to +150
C. Three package styles provide a magnetically
optimized package for most applications. Suffix `LH' is a miniature
SOT23W low-profile surface-mount package, `LT' is a miniature
SOT89/TO-243AA transistor package for surface-mount applications;
while suffix `UA' is a three-lead ultra-mini-SIP for through-hole
mounting.
Data Sheet
27609.20
FEATURES
s Symmetrical Switch Points
s Resistant to Physical Stress
s Superior Temperature Stability
s Output Short-Circuit Protection
s Operation From Unregulated Supply
s Reverse Battery Protection
s Solid-State Reliability
s Small Size
3280, 3281,
AND
3283
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
C
Supply Voltage, V
CC
........................ 26.5 V
Reverse Battery Voltage, V
RCC
.......... -30 V
Magnetic Flux Density, B ........... Unlimited
Output Off Voltage, V
OUT
................... 26 V
Continuous Output Current,
I
OUT
.......................................... 25 mA*
Reverse Output Current, I
OUT
........ -50 mA
Package Power Dissipation, P
D
. See Graph
Junction Temperature, T
J
............... +170
C
Operating Temperature Range, T
A
Suffix `E' .................. -40
C to +85
C
Suffix `L' ................ -40
C to +150
C
Storage Temperature Range,
T
S
.............................. -65
C to +170
C
*Internal current limiting is intended to protect
the device from output short circuits.
Pinning is shown viewed from branded side.
Always order by complete part number: the prefix `A' + the basic four-
digit part number + a suffix to indicate operating temperature range +
a suffix to indicate package style, e.g., A3281ELH .
CHOPPER-STABILIZED, PRECISION
HALL-EFFECT LATCHES
Dwg. PH-003-2
1
SUPPLY
V
CC
GROUND
3
2
OUTPUT
X
PTCT
Suffix 'LT' & 'UA' Pinning
(SOT89/TO-243AA & ultra-mini SIP)
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2
FUNCTIONAL BLOCK DIAGRAM
Copyright 2000, 2002 Allegro MicroSystems, Inc.
Suffix `LH' Pinning
(SOT23W)
Dwg. PH-003-4
SUPPLY
GROUND
OUTPUT
V
CC
X
PTCT
1
2
3
600
400
200
20
60
100
140
0
AMBIENT TEMPERATURE in
C
ALLOWABLE PACKAGE POWER DISSIPATION in MILLIWATTS
Dwg. GH-046-2D
Suffix "UA"
R
JA
= 165
C/W
40
80
120
180
700
500
300
100
160
Suffix "LT"
R
JA
= 180
C/W
800
Suffix "E"
Suffix "L"
Suffix "LH"
R
JA
= 228
C/W
Dwg. FH-020-1
GROUND
OUTPUT
<1
X
DYNAMIC
OFFSET CANCELLATION
SUPPLY
CONTROL
CURRENT
LIMIT
REG.
SAMPLE
& HOLD
LOW-PASS
FILTER
TO ALL
SUBCIRCUITS
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
www.allegromicro.com
3
Part Numbers
1
A3280
A3281A3283
Characteristic
Test Conditions
Min.
Typ.
Max.
Min.
Typ.
Max.
Min.
Typ.
Max.
Units
Operate Point, B
OP
at T
A
= +25
C and T
A
= max.
5.0
22
40
15
50
90
100
150
180
G
at T
A
= -40
C
5.0
40
15
90
100
200
G
Release Point, B
RP
at T
A
= +25
C and T
A
= max.
-40
-23
-5.0
-90
-50
-15
-180
-150
-100
G
at T
A
= -40
C
-40
-5.0
-90
-15
-200
-100
G
Hysteresis, B
hys
at T
A
= +25
C and T
A
= max.
10
45
80
30
100
180
300
360
G
(B
OP
- B
RP
)
at T
A
= -40
C
80
180
360
G
NOTES:1. Complete part number includes a suffix to identify operating temperature range (E or L) and
package type (LH, LT, or UA).
2. As used here, negative flux densities are defined as less than zero (algebraic convention) and -50 G is less than +10 G.
3. Typical Data is at T
A
= +25
C and V
CC
= 12 V and is for design information only.
4. 1 gauss (G) is exactly equal to 0.1 millitesla (mT).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage Range
V
CC
Operating, T
J
< 170
C
1
4.2
24
V
Output Leakage Current
I
OFF
V
OUT
= 24 V, B < B
RP
10
A
Output Saturation Voltage
V
OUT(SAT)
I
OUT
= 20 mA, B > B
OP
185
500
mV
Output Current Limit
I
OM
B > B
OP
30
60
mA
Power-On Time
t
po
V
CC
> 4.2 V
50
s
Chopping Frequency
f
C
340
kHz
Output Rise Time
t
r
R
L
= 820
, C
L
= 20 pF
0.2
2.0
s
Output Fall Time
t
f
R
L
= 820
, C
L
= 20 pF
0.1
2.0
s
Supply Current
I
CC
B < B
RP
, V
CC
= 12 V
3.0
8.0
mA
B > B
OP
, V
CC
= 12 V
4.0
8.0
mA
Reverse Battery Current
I
CC
V
RCC
= -30 V
-5.0
mA
Zener Voltage
V
Z
+ V
D
I
CC
= 15 mA, T
A
= 25
C
28
32
37
V
Zener Impedance
z
z
+ z
D
I
CC
= 15 mA, T
A
= 25
C
50
NOTES:1.Maximum voltage must be adjusted for power dissipation and junction temperature.
2. B
OP
= operate point (output turns on); B
RP
= release point (output turns off).
3. Typical Data is at T
A
= +25
C and V
CC
= 12 V and is for design information only.
ELECTRICAL CHARACTERISTICS over operating temperature range.
MAGNETIC CHARACTERISTICS over operating voltage range.
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
4
TYPICAL OPERATING CHARACTERISTICS
as a function of temperature
0
50
100
AMBIENT TEMPERATURE IN
C
-50
Dwg. GH-026-3
SWITCH POINTS IN GAUSS
0
10
OPERATE POINT
150
-25
25
75
125
20
30
40
50
-50
-40
-30
-20
-10
V
CC
= 4.5 V
V
CC
= 24 V
RELEASE POINT
0
50
100
AMBIENT TEMPERATURE IN
C
-50
Dwg. GH-026-4
SWITCH POINTS IN GAUSS
0
20
OPERATE POINT
150
-25
25
75
125
40
60
80
100
-100
-80
-60
-40
-20
V
CC
= 4.5 V to 24 V
RELEASE POINT
* Complete part number includes a suffix denoting operating temperature range (E or L) and package type (LH, LT, or UA).
A3283* SWITCH POINTS
A3280* SWITCH POINTS
A3281* SWITCH POINTS
0
50
100
AMBIENT TEMPERATURE IN
C
-50
Dwg. GH-026-6
SWITCH POINTS IN GAUSS
0
40
OPERATE POINT
150
-25
25
75
125
80
120
160
200
-200
-160
-120
-80
-40
V
CC
= 4.5 V
V
CC
= 24 V
RELEASE POINT
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
www.allegromicro.com
5
* Complete part number includes a suffix denoting operating temperature range (E or L) and package type (LH, LT, or UA).
4.0
4.5
5.0
SUPPLY VOLTAGE IN VOLTS
3.0
Dwg. GH-021-1
3.5
RELEASE POINT
SWITCH POINT IN GAUSS
80
40
0
-40
-80
OPERATE POINT
24
T
A
= 150
C
T
A
= -40
C
4.0
4.5
5.0
SUPPLY VOLTAGE IN VOLTS
3.0
Dwg. GH-021-3
3.5
RELEASE POINT
SWITCH POINT IN GAUSS
40
20
0
-20
-40
OPERATE POINT
24
T
A
= 150
C
T
A
= -40
C
TYPICAL OPERATING CHARACTERISTICS
as a function of temperature (cont'd)
0
25
50
75
100
300
0
AMBIENT TEMPERATURE IN
C
200
100
-50
Dwg. GH-029-4
SATURATION VOLTAGE IN mV
150
-25
125
I
OUT
= 20 mA
V
CC
= 12 V
6.0
SUPPLY CURRENT IN mA
5.0
4.0
3.0
2.0
0
25
50
75
100
AMBIENT TEMPERATURE IN
C
-50
Dwg. GH-028-5
125
-25
150
OUTPUT ON, B > B
OP
OUTPUT OFF, B < B
RP
V
CC
= 12 V
SUPPLY CURRENT
OUTPUT SATURATION VOLTAGE
A3280* SWITCH POINTS
A3281* SWITCH POINTS
TYPICAL OPERATING CHARACTERISTICS
as a function of supply voltage
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
6
SENSOR LOCATIONS
(
0.005" [0.13 mm] die placement)
Package Designator `LH'
Package Designator `UA'
0.038"
0.96 mm
1
2
Dwg. MH-025
0.011"
0.28 mm
NOM
ACTIVE AREA DEPTH
0.059"
1.49 mm
A
3
Package Designator `LT'
Although sensor location is accurate to three sigma for a
particular design, product improvements may result in small
changes to sensor location.
TYPICAL OPERATING CHARACTERISTICS
as a function of supply voltage (cont'd)
4.0
4.5
5.0
SUPPLY VOLTAGE IN VOLTS
3.0
Dwg. GH-055-1
3.5
24
T
A
= 150
C
T
A
= +25
C
T
A
= -40
C
I
OUT
= 20 mA
250
150
SATURATION VOLTAGE IN mV
200
225
175
4.0
6.0
9.0
SUPPLY VOLTAGE IN VOLTS
3.0
Dwg. GH-058-4
5.0
12
T
A
= 150
C
T
A
= +25
C
T
A
= -40
C
7.0
5.0
3.0
1.0
SUPPLY CURRENT IN mA
6.0
4.0
2.0
8.0
0
OUTPUT ON
10
11
8.0
7.0
SUPPLY CURRENT
OUTPUT SATURATION VOLTAGE
0.045"
1.14 mm
1
3
2
Dwg. MH-008-8A
0.0305"
0.775 mm
NOM
ACTIVE AREA DEPTH
0.088"
2.24 mm
A
1
3
2
Dwg. MH-011-9B
0.0195"
0.50 mm
NOM
BRANDED
SURFACE
ACTIVE AREA DEPTH
0.080"
2.04 mm
0.056"
1.44 mm
A
Allegro
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
www.allegromicro.com
7
All Allegro sensors are subjected to stringent qualification requirements prior to being released to production.
To become qualified, except for the destructive ESD tests, no failures are permitted.
CRITERIA FOR DEVICE QUALIFICATION
Qualification Test
Test Method and Test Conditions
Test Length
Samples
Comments
Biased Humidity (HAST)
T
A
= 130
C, RH = 85%
50 hrs
77
V
CC
= V
OUT
= 5 V
High-Temperature
JESD22-A108,408 hrs
77
V
CC
= 24 V,
Operating Life (HTOL)
T
A
= 150
C, T
J
170
C
V
OUT
= 20 V
Accelerated HTOL
JESD22-A108,504 hrs
77
V
CC
= 24 V,
T
A
= 175
C, T
J
190
C
V
OUT
= 20 V
Autoclave, Unbiased
JESD22-A102, Condition C,
96 hrs
77
T
A
= 121
C, 15 psig
High-Temperature
MIL-STD-883, Method 1008,
1000 hrs
77
(Bake) Storage Life
T
A
= 170
C
Temperature Cycle
MIL-STD-883, Method 1010,
500 cycles
77
-65
C to +150
C
Latch-Up
--
Pre/Post
6
Reading
Electro-Thermally
--
Pre/Post
6
Induced Gate Leakage
Reading
ESD,CDF-AEC-Q100-002
Pre/Post
3 per
Test to failure,
Human Body Model
Reading
test
All leads > 1500 V
ESD,JESD22-A115
Pre/Post
3 per
Test to failure,
Machine Model
Reading
test
All leads > 200 V
Electrical Distributions
Per Specification
--
30
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8
FUNCTIONAL DESCRIPTION
Chopper-Stabilized Technique. The Hall element can be
considered as a resistor array similar to a Wheatstone bridge. A
large portion of the offset is a result of the mismatching of these
resistors. These devices use a proprietary dynamic offset
cancellation technique, with an internal high-frequency clock to
reduce the residual offset voltage of the Hall element that is
normally caused by device overmolding, temperature dependen-
cies, and thermal stress. The chopper-stabilizing technique
cancels the mismatching of the resistor circuit by changing the
direction of the current flowing through the Hall plate using
CMOS switches and Hall voltage measurement taps, while
maintaing the Hall-voltage signal that is induced by the external
magnetic flux. The signal is then captured by a sample-and-
hold circuit and further processed using low-offset bipolar
circuitry. This technique produces devices that have an
extremely stable quiescent Hall output voltage, are immune to
thermal stress, and have precise recoverability after temperature
cycling. This technique will also slightly degrade the device
output repeatability. A relatively high sampling frequency is
used in order that faster signals can be processed.
More detailed descriptions of the circuit operation can be
found in: Technical Paper STP 97-10, Monolithic Magnetic
Hall Sensor Using Dynamic Quadrature Offset Cancellation
and Technical Paper STP 99-1, Chopper-Stabilized Amplifiers
With A Track-and-Hold Signal Demodulator.
Operation. The output of these devices switches low (turns
on) when a magnetic field perpendicular to the Hall sensor
exceeds the operate point threshold (B
OP
). After turn-on, the
output is capable of sinking 25 mA and the output voltage is
V
OUT(SAT)
. Note that the device latches; that is, a south pole of
sufficient strength towards the branded surface of the device
will turn the device on; removal of the south pole will leave the
device on. When the magnetic field is reduced below the
release point (B
RP
), the device output goes high (turns off). The
difference in the magnetic operate and release points is the
hysteresis (B
hys
) of the device. This built-in hysteresis allows
clean switching of the output even in the presence of external
mechanical vibration and electrical noise.
Powering up in the absence of a magnetic field (less than
B
OP
and higher than B
RP
) will allow an indeterminate output
state. The correct state is warranted after the first excursion
beyond B
OP
or B
RP
.
Dwg. EH-012
REG
SAMPLE
& HOLD
X
+V
HALL
VOLTAGE
B
+
--
Dwg. AH-011-2
0
+B
0
OUTPUT VOLTAGE
FLUX DENSITY
Dwg. GH-034-5
-B
RP
B
V
OUT(SAT)
CC
V
OP
B
+V
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
www.allegromicro.com
9
It is strongly recommended that an external bypass capacitor be connected (in close proximity to the Hall sensor) between the
supply and ground of the device to reduce both external noise and noise generated by the chopper-stabilization technique.
The simplest form of magnet that will operate these devices is a ring magnet. Other methods of operation, such as linear
magnets, are possible.
Extensive applications information for Hall-effect sensors is available in:
Hall-Effect IC Applications Guide, Application Note 27701;
Hall-Effect Devices: Soldering, Gluing, Potting, Encapsulating, and Lead Forming, Application Note 27703.1;
Soldering of Through-Hole Hall-Sensor Dervices, Application Note 27703; and
Soldering of Surface-Mount Hall-Sensor Devices, Application Note 27703.2.
More detailed descriptions of the chopper-stabilized circuit operation can be found in:
Monolithic Magnetic Hall Sensor Using Dynamic Quadrature Offset Cancelation, Technical Paper STP 97-10; and
Chopper-Stabilized Amplifiers With A Track-and-Hold Signal Demodulator, Technical Paper STP 99-1.
All are provided in Allegro Electronic Data Book, AMS-702. or at
www.allegromicro.com
SUPPLY
OUTPUT
Dwg. EH-013
0.1
F
SUPPLY
1
V
CC
3
2
X
PTCT
APPLICATIONS INFORMATION
The products described herein are manufactured under one or
more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283;
5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719;
5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents
pending.
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be required
to permit improvements in the performance, 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 products are not authorized for use as critical components
in life-support appliances, devices, or systems without express written
approval.
The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsi-
bility for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
10
PACKAGE DESIGNATOR `LH'
(SOT23W, fits SC-74A solder-pad layout)
NOTES: 1.
Tolerances on package height and width represent allowable mold offsets. Dimensions given are
measured at the widest point (parting line).
2.
Exact body and lead configuration at vendor's option within limits shown.
3.
Height does not include mold gate flash.
4.
Where no tolerance is specified, dimension is nominal.
5.
Add "LT" to part number for tape and reel.
Dimensions in Inches
(for reference only)
Dimensions in Millimeters
(controlling dimensions)
Dwg. MA-011-3 in
1
2
0.039
0.094
0.037
0.028
3
Dwg. MA-011-3 mm
1
2
1.00
2.40
0.95
0.70
3
Dwg. MA-010-3C in
1
2
0.006
0.000
0.0079
0.0050
0.083
0.073
0.118
0.106
0.037
BSC
0.022
REF
0.020
0.012
3
0.045
0.032
0
TO
8
0.020
MIN
GAUGE PLANE
SEATING PLANE
0.020
BSC
0.122
0.114
Dwg. MA-010-3C mm
1
2
0.15
0.00
0.20
0.127
2.10
1.85
3.00
2.70
0.95
BSC
0.55
REF
0.50
0.30
3
1.13
0.87
0
TO
8
0.25
MIN
GAUGE PLANE
SEATING PLANE
0.25
BSC
3.10
2.90
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
www.allegromicro.com
11
Dwg. MA-009-3A in
1
2
3
0.072
0.064
0.167
0.155
0.059
BSC
0.0189
0.0142
0.047
0.035
0.102
0.090
0.063
0.055
0.0173
0.0138
0.090
0.084
0.0221
0.0173
0.118
BSC
0.181
0.173
Dwg. MA-009-3A mm
1
2
3
4.60
4.40
1.83
1.62
4.25
3.94
1.50
BSC
0.48
0.36
1.20
0.89
2.60
2.29
1.60
1.40
0.44
0.35
2.29
2.13
0.56
0.44
3.00
BSC
PACKAGE DESIGNATOR `LT'
(SOT89/TO-243AA)
Dimensions in Inches
(for reference only)
Dimensions in Millimeters
(controlling dimensions)
NOTES: 1.
Exact body and lead configuration at vendor's option within limits shown.
2.
Supplied in bulk pack (500 pieces per bag) or add "TR" to part number for tape and reel.
3.
Only low-temperature (
240
C) reflow-soldering techniques are recommended for SOT89 devices.
1
B
0.098
0.031
0.102
0.047
0.181
0.079
Dwg. MA-012-3 in
Pads 1, 2, 3, and A -- Standard SOT89 Layout
Pads 1, 2, 3, and B -- Low-Stress Version
Pads 1, 2, and 3 only -- Lowest Stress, But Not Self Aligning
2
0.028
TYP
0.031
TYP
A
3
1
3
B
2.5
0.8
2.6
1.2
4.6
2.0
Dwg. MA-012-3 mm
Pads 1, 2, 3, and A -- Standard SOT89 Layout
Pads 1, 2, 3, and B -- Low-Stress Version
Pads 1, 2, and 3 only -- Lowest Stress, But Not Self Aligning
2
0.7
TYP
0.8
TYP
A
3280, 3281,
AND
3283
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT LATCHES
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
12
Dimensions in Inches
(controlling dimensions)
Dimensions in Millimeters
(for reference only)
PACKAGE DESIGNATOR `UA'
NOTES: 1.
Tolerances on package height and width represent
allowable mold offsets. Dimensions given are
measured at the widest point (parting line).
2.
Exact body and lead configuration at vendor's option
within limits shown.
3.
Height does not include mold gate flash.
4.
Recommended minimum PWB hole diameter to clear
transition area is 0.035" (0.89 mm).
5.
Where no tolerance is specified, dimension is nominal.
6.
Supplied in bulk pack (500 pieces per bag).
Dwg. MH-014E in
0.164
0.159
0.062
0.058
0.0173
0.0138
0.050
BSC
45
0.640
0.600
0.0189
0.0142
0.085
MAX
45
0.031
1
2
3
0.122
0.117
SEE NOTE
Dwg. MH-014E mm
4.17
4.04
1.57
1.47
0.44
0.35
1.27
BSC
45
16.26
15.24
0.48
0.36
2.16
MAX
45
0.79
1
2
3
3.10
2.97
SEE NOTE
Radial Lead Form (order A328xxUA-LC)
NOTE:
Lead-form dimensions are the nominals produced on the
forming equipment. No dimensional tolerance is implied or
guaranteed for bulk packaging (500 pieces per bag).
0.620"
0.500"
(15.7 mm
12.7 mm)
0.100"
(2.5 mm)
Dwg. MH-026
0.108"
(2.74 mm)
1
2
3
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