Allegro A3240ELT Chopper-stabilized, precision hall-effect switch Datasheet

Data Sheet
27621.20b
3240
CHOPPER-STABILIZED, PRECISION
HALL-EFFECT SWITCH
Suffix ‘–LT’ & ‘–UA’ Pinning
X
(SOT89/TO-243AA & ultra-min SIP)
PTCT
CC
2
3
OUTPUT
SUPPLY
1
GROUND
V
Dwg. PH-003-2
The A3240-- Hall-effect switch is an extremely temperature-stable
and stress-resistant sensor 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 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. 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 modified
SOT23W surface-mount package, ‘–LT’ is a miniature SOT89/TO243AA transistor package for surface-mount applications; while suffix
‘–UA’ is a three-lead ultra-mini-SIP for through-hole mounting.
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
at TA = +25°C
Supply Voltage, VCC ........................ 26.5 V
Reverse Battery Voltage, VRCC .......... -30 V
Magnetic Flux Density, B ........... Unlimited
Output OFF Voltage, VOUT ................. 26 V
Continuous Output Current,
IOUT .......................................... 25 mA*
Reverse Output Current, IOUT ........ -50 mA
Package Power Dissipation, PD . See Graph
Junction Temperature, TJ ............... +165°C
Operating Temperature Range, TA
Suffix ‘E–’ .................. -40°C to +85°C
Suffix ‘L–’ ................ -40°C to +150°C
Storage Temperature Range,
TS .............................. -65°C to +170°C
*Internal current limiting is intended to protect
the device from output short circuits.
FEATURES
■
■
■
■
■
■
■
Resistant to Physical Stress
Superior Temperature Stability
Output Short-Circuit Protection
Operation From Unregulated Supply
Reverse Battery Protection
Solid-State Reliability
Small Size
Always order by complete part number: the prefix ‘A’ + the basic fourdigit part number + a suffix to indicate operating temperature range +
a suffix to indicate package style, e.g., A3240ELH .
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
FUNCTIONAL BLOCK DIAGRAM
SUPPLY
OUTPUT
LOW-PASS
FILTER
X
TO ALL
SUBCIRCUITS
SAMPLE
& HOLD
DYNAMIC
OFFSET CANCELLATION
REG.
CONTROL
CURRENT
LIMIT
<1Ω
GROUND
Dwg. FH-020-1
Suffix ‘–LH’ Pinning
(SOT23W)
700
Suffix "–UA"
RθJA = 165°C/W
3
X
600
500
Suffix "–LT"
RθJA = 180°C/W
Suffix "–LH"
RθJA = 228°C/W
PTCT
400
300
V
CC
1
200
20
40
60
100
80
120
AMBIENT TEMPERATURE in °C
140
160
OUTPUT
Suffix "L–"
GROUND
100
0
180
Dwg. PH-003-4
Dwg. GH-046-2D
2
2
Suffix "E–"
SUPPLY
ALLOWABLE PACKAGE POWER DISSIPATION in MILLIWATTS
800
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2000, 2003, 2004 Allegro MicroSystems, Inc.
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
ELECTRICAL CHARACTERISTICS over operating temperature range.
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
4.2
–
24
V
Supply Voltage Range
VCC
Operating, TJ < 165°C1
Output Leakage Current
IOFF
VOUT = 24 V, B < BRP
–
–
10
µA
VOUT(SAT)
IOUT = 20 mA, B > BOP
–
185
500
mV
Output Saturation Voltage
Output Current Limit
IOM
B > BOP
30
–
60
mA
Power-On Time
tpo
VCC > 4.2 V
–
–
50
µs
Chopping Frequency
fC
–
340
–
kHz
Output Rise Time
tr
RL = 820 Ω, CL = 20 pF
–
0.2
2.0
µs
Output Fall Time
tf
RL = 820 Ω, CL = 20 pF
–
0.1
2.0
µs
B < BRP, VCC = 12 V
–
3.0
6.0
mA
B > BOP, VCC = 12 V
–
4.0
6.0
mA
VRCC = -30 V
–
–
-5.0
mA
Supply Current
Reverse Battery Current
ICC
ICC
Zener Voltage
VZ + VD
ICC = 15 mA, TA = 25°C
28
32
37
V
Zener Impedance
zz + z D
ICC = 15 mA, TA = 25°C
–
50
–
Ω
NOTES:1. Maximum voltage must be adjusted for power dissipation and junction temperature.
2. BOP = operate point (output turns on); BRP = release point (output turns off).
3. Typical Data is at TA = +25°C and VCC = 12 V and is for design information only.
MAGNETIC CHARACTERISTICS over operating supply voltage and temperature ranges.
Limits
Characteristic
Symbol
Operate Point
Test Conditions
Min.
Typ.
Max.
Units
BOP
–
35
50
G
Release Point
BRP
5.0
25
–
G
Hysteresis
Bhys
–
10
–
G
BOP - BRP
NOTES: 1. Typical Data is at TA = +25°C and VCC = 12 V and is for design information only.
2. 1 gauss (G) is exactly equal to 0.1 millitesla (mT).
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3
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
TYPICAL OPERATING CHARACTERISTICS
as a function of temperature
SWITCH POINTS
50
SWITCH POINTS IN GAUSS
40
OPERATE POINT
30
RELEASE POINT
20
VCC = 4.5 V
VCC = 24 V
10
0
-50
-25
0
25
50
75
100
125
AMBIENT TEMPERATURE IN ° C
150
Dwg. GH-026-5
OUTPUT SATURATION VOLTAGE
SUPPLY CURRENT
300
6.0
IOUT = 20 mA
VCC = 12 V
5.0
SUPPLY CURRENT IN mA
SATURATION VOLTAGE IN mV
VCC = 12 V
200
100
4.0
OUTPUT ON, B > BOP
3.0
OUTPUT OFF, B < BRP
0
-50
-25
0
25
50
75
100
125
150
AMBIENT TEMPERATURE IN ° C
2.0
-50
-25
0
25
Dwg. GH-029-4
4
50
75
100
125
150
AMBIENT TEMPERATURE IN ° C
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Dwg. GH-028-5
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
TYPICAL OPERATING CHARACTERISTICS
as a function of supply voltage
SWITCH POINTS
40
OPERATE POINT
SWITCH POINT IN GAUSS
30
RELEASE POINT
TA = 150°C
TA = -40°C
20
10
0
3.0
3.5
4.0
4.5
24
5.0
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-021-2
OUTPUT SATURATION VOLTAGE
SUPPLY CURRENT
250
8.0
OUTPUT ON
TA = 150°C
TA = +25°C
TA = -40°C
7.0
225
6.0
SUPPLY CURRENT IN mA
SATURATION VOLTAGE IN mV
IOUT = 20 mA
TA = 150°C
TA = +25°C
TA = -40°C
200
175
5.0
4.0
3.0
2.0
1.0
150
3.0
3.5
4.0
4.5
5.0
24
4.0
5.0
6.0
7.0
8.0
9.0
SUPPLY VOLTAGE IN VOLTS
SUPPLY VOLTAGE IN VOLTS
Dwg. GH-055-1
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0
3.0
10
11
12
Dwg. GH-058-4
5
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
SENSOR LOCATIONS
Package Designator ‘LH’
ACTIVE AREA DEPTH
0.011"
0.28 mm
NOM
0.059"
1.49 mm
3
0.038"
0.96 mm
A
1
2
Dwg. MH-025
Package Designator ‘LT’
ACTIVE AREA DEPTH
0.0305"
0.775 mm
NOM
0.088"
2.24 mm
0.045"
1.14 mm
A
1
2
3
Dwg. MH-008-8A
Package Designator ‘UA’
ACTIVE AREA DEPTH
0.0195"
0.50 mm
NOM
0.080"
2.04 mm
Allegro
0.056"
1.44 mm
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.
A
BRANDED
SURFACE
1
2
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.
3
Dwg. MH-011-9B
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 responsibility for its use; nor for any infringements of patents or other rights of
third parties that may result from its use.
6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
FUNCTIONAL DESCRIPTION
SAMPLE
& HOLD
REG
X
B
+V
Dwg. EH-012
—
HALL
VOLTAGE
+
Dwg. AH-011-2
+V
VCC
OUTPUT VOLTAGE
B RP
B OP
VOUT(SAT)
0
0
+B
FLUX DENSITY
Dwg. GH-007-2
3
SUPPLY
OUTPUT
2
PTCT
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 dependencies, 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-andhold 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 (south pole) perpendicular to the Hall
sensor exceeds the operate point threshold (BOP). After turn-on,
the output is capable of sinking 25 mA and the output voltage is
VOUT(SAT). When the magnetic field is reduced below the
release point (BRP), the device output goes high (turns off). The
difference in the magnetic operate and release points is the
hysteresis (Bhys) of the device. This built-in hysteresis allows
clean switching of the output even in the presence of external
mechanical vibration and electrical noise.
Applications. 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 chopperstabilization 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 on
magnets and Hall-effect sensors is also available in Application
Note 27701, or at
www.allegromicro.com
V
1
CC
0.1 µF
SUPPLY
X
Dwg. EH-013
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7
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR ‘LH’
(fits SC-59A solder-pad layout)
Dimensions in Inches
(for reference only)
Dimensions in Millimeters
(controlling dimensions)
0.122
0.114
3.10
2.90
0.020
0.012
0.083
0.073
0.50
0.30
3
1
2
0.118
0.106
2.10
1.85
0.010
BSC
3.00
2.70
3
1
2
GAUGE PLANE
REF
0° TO 8°
0.037
0.006
0.000
0.045
0.032
SEATING PLANE
0.55
0.010
REF
0° TO 8°
0.95
MIN
BSC
BSC
GAUGE PLANE
SEATING PLANE
0.022
0.25
MIN
BSC
0.0079
0.0050
0.15
0.00
1.13
0.87
0.20
0.127
Dwg. MA-010-3D in
Dwg. MA-010-3D mm
0.028
0.70
3
3
0.039
1.00
0.094
1
2
2.40
1
2
0.037
0.95
Dwg. MA-011-3 in
Dwg. MA-011-3 mm
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.
8
0.25
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR ‘LT’
(SOT89/TO-243AA)
Dimensions in Inches
(for reference only)
0.181
0.173
0.072
0.064
0.167
0.155
1
2
0.063
0.055
0.102
0.090
3
Dimensions in Millimeters
(controlling dimensions)
0.0173
0.0138
0.090
0.084
4.25
3.94
0.0189
0.0142
0.0221
0.0173
0.047
0.035
0.059
4.60
4.40
1.83
1.62
3.00
BSC
Dwg. MA-009-3A in
Dwg. MA-009-3A mm
2.5
2.0
0.098
0.079
B
B
0.031
0.102
A
0.8
2.6
A
4.6
0.181
1
2
2.29
2.13
0.56
0.44
1.50
0.118
BSC
2.60
2.29
3
0.44
0.35
0.48
0.36
1.20
0.89
BSC
BSC
2
1
1.60
1.40
3 0.047
1
2
3
1.2
0.028
0.031
0.7
0.8
TYP
TYP
TYP
TYP
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
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
Dwg. MA-012-3 in
Dwg. MA-012-3 mm
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.
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9
3240
CHOPPER-STABILIZED,
PRECISION
HALL-EFFECT SWITCH
PACKAGE DESIGNATOR ‘UA’
Dimensions in Millimeters
(for reference only)
Dimensions in Inches
(controlling dimensions)
0.164
0.159
4.17
4.04
0.062
0.058
45°
1.57
1.47
45°
3.10
2.97
0.122
0.117
45°
45°
0.085
1
2
3
0.031
2.16
1
2
0.79
3
MAX
MAX
0.640
0.600
16.26
15.24
0.0173
0.0138
0.0189
0.0142
SEE NOTE
0.44
0.35
0.48
0.36
SEE NOTE
1.27
0.050
BSC
BSC
Dwg. MH-014E in
Dwg. MH-014E mm
Radial Lead Form (order A3240xUA-LC)
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).
1
2
3
0.108"
(2.74 mm)
0.620"
0.500"
(15.7 mm
12.7 mm)
0.100"
(2.5 mm)
Dwg. MH-026
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).
10
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000