A3241 and A3242
Chopper-Stabilized
Unipolar Hall-Effect Switches
Package LH, 3-pin Surface Mount
GND
3
The A3241 and A3242 integrated circuits are unipolar Hall-effect switches with
digital outputs. These sensors are suited for operation over extended temperature
ranges, up to +150°C. Superior high-temperature performance is made pos-
sible through an Allegro
®
patented dynamic offset cancellation, which reduces
the residual offset voltage normally caused by device overmolding, temperature
excursions, and thermal stress.
The A3241 and A3242 Hall-effect switches include the following on a single
silicon chip: voltage regulator, Hall-voltage generator, small-signal amplifier,
chopper stabilization, Schmitt trigger, and a short circuit protected open-drain
output. Advanced BiCMOS wafer fabrication processing is used to take advantage
of low-voltage requirements, component matching, very low input-offset errors,
and small component geometries.
The integrated voltage regulator permits operation from 3.6 to 24 V. The unipolar
family members operate with a sufficient south polarity
fi
eld only, turning off in
the absence of such a south polarity
fi
eld.
The A3241 and A3242 are rated for operation between the ambient temperatures
–40°C and 85°C for the E temperature range, and –40°C to 150°C for the L tem-
perature range. The small geometries of the BiCMOS process allow these devices
to be provided in ultrasmall packages. The package styles available provide mag-
netically optimized solutions for most applications. Package LH is an SOT23W,
a miniature low-profile surface-mount package, while package UA is a three-lead
ultramini SIP for through-hole mounting. Each package is available in a lead (Pb)
free version, with 100% matte tin plated leadframes.
1
2
1
2
3
Package UA, 3-pin SIP
1
2
VOUT
GND
VCC
VOUT
3
VCC
1 2
3
Features and Benefits
Chopper stabilization
Output short circuit protection
Solid state reliability
Small size
Robust EMC capability
High ESD ratings (HBM)
Superior temperature stability
Extremely low switchpoint drift
Insensitive to physical stress
Reverse battery protection
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
..........................................
28 V
Reverse-Supply Voltage, V
RCC
........................
–18 V
Reverse-Supply Current, I
RCC
........................–2
mA
Output Off Voltage, V
OUT
..................................
28 V
Output Current, I
OUTSINK
...........
Internally Limited
Magnetic Flux Density, B .........................Unlimited
Operating Temperature
Ambient, T
A
, Range E..................
–40ºC to 85ºC
Ambient, T
A
, Range L................
–40ºC to 150ºC
Maximum Junction, T
J(MAX)
......................165ºC
Storage Temperature, T
S
..................
–65ºC to 170ºC
A3241-DS, Rev. 2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
A3241 and A3242
Chopper-Stabilized Unipolar Hall Effect Switches
Product Selection Guide
Part Number
Pb-
free
Packing*
Mounting
3-pin SOT23W surface mount
–40 to 85
3-pin SIP through hole
40
3-pin SOT23W surface mount
–40 to 150
3-pin SIP through hole
3-pin SOT23W surface mount
–40 to 85
3-pin SIP through hole
110
3-pin SOT23W surface mount
–40 to 150
3-pin SIP through hole
200
135
Ambient, T
A
(°C)
B
RP(MIN)
(G)
B
OP(MAX)
(G)
A3241ELHLT
–
7-in. reel, 3000 pieces/reel
A3241ELHLT-T
Yes
A3241EUA
–
Bulk, 500 pieces/bag
A3241EUA-T
Yes
A3241LLHLT
–
7-in. reel, 3000 pieces/reel
A3241LLHLT-T
Yes
A3241LUA
–
Bulk, 500 pieces/bag
A3241LUA-T
Yes
A3242ELHLT
–
7-in. reel, 3000 pieces/reel
A3242ELHLT-T
Yes
A3242EUA
–
Bulk, 500 pieces/bag
A3242EUA-T
Yes
A3242LLHLT
–
7-in. reel, 3000 pieces/reel
A3242LLHLT-T
Yes
A3242LUA
–
Bulk, 500 pieces/bag
A3242LUA-T
Yes
*Contact Allegro for additional packing options.
Functional Block Diagram
VCC
Regulator
To All Subcircuits
Sample and Hold
Dynamic Offset
Cancellation
Low-Pass
Filter
VOUT
Amp
Amp
Control
Current Limit
<1Ω
GND
Terminal List
Name
VCC
VOUT
GND
Description
Connects power supply to chip
Output from circuit
Ground
Number
Package LH
1
2
3
Package UA
1
3
2
A3241-DS, Rev. 2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
2
A3241 and A3242
Chopper-Stabilized Unipolar Hall Effect Switches
OPERATING CHARACTERISTICS
valid over full operating voltage and ambient temperature ranges, unless otherwise noted
Characteristic
Electrical Characteristics
Supply Voltage
1
Output Leakage Current
Output On Voltage
Output Current Limit
Power-On Time
Chopping Frequency
Output Rise Time
2
Output Fall Time
2
Supply Current
Reverse Battery Current
Supply Zener Clamp Voltage
Supply Zener Current
3
Magnetic Characteristics
4
Operate Point
Release Point
Hysteresis
1
2
Symbol
V
CC
I
OUTOFF
V
OUT(SAT)
I
OM
t
PO
f
c
t
r
t
f
I
CCON
I
CCOFF
I
RCC
V
ZSupply
I
ZSupply
Test Conditions
Operating, T
J
< 165°C
V
OUT
= 24 V, B < B
RP
I
OUT
= 20 mA, B > B
OP
B > B
OP
V
CC
> V
CC(MIN)
R
LOAD
= 820
Ω,
C
S
= 20 pF
R
LOAD
= 820
Ω,
C
S
= 20 pF
B > B
OP
B < B
RP
V
RCC
= –18 V
I
CC
= 6.5 mA; T
A
= 25°C
V
S
= 28 V
A3241
A3242
A3241
A3242
A3241
A3242
B
OP
– B
RP
Min.
3.6
–
–
30
–
–
–
–
–
–
–
28
–
50
120
40
110
10
10
Typ.
–
–
–
–
–
200
–
–
1.5
1.5
–
–
–
95
150
70
125
25
25
Max.
24
10
500
60
50
–
1
1
3.5
3.5
–2
–
6.5
135
200
110
190
42
40
Units
V
μA
mV
mA
μs
kHz
μs
μs
mA
mA
mA
V
mA
G
G
G
G
G
G
B
OP
B
RP
B
HYS
Maximum voltage must be adjusted for power dissipation and junction temperature, see
Power Derating
section.
C
S
= oscilloscope probe capacitance.
3
Maximum current limit is equal to the maximum I
CC(MAX)
+ 3 mA.
4
Magnetic
fl
ux density, B, is indicated as a negative value for north-polarity magnetic
fi
elds, and as a positive value for south-polarity magnetic
fi
elds.
This so-called algebraic convention supports arithmetic comparison of north and south polarity values, where the relative strength of the
fi
eld is indicated
by the absolute value of B, and the sign indicates the polarity of the
fi
eld (for example, a –100 G
fi
eld and a 100 G
fi
eld have equivalent strength, but
opposite polarity).
DEVICE QUALIFICATION PROGRAM
Contact Allegro for information.
EMC (Electromagnetic Compatibility) REQUIREMENTS
Contact Allegro for information.
A3241-DS, Rev. 2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
3
A3241 and A3242
Chopper-Stabilized Unipolar Hall Effect Switches
Characteristic Data
Supply Current (On) versus Ambient Temperature
5.0
4.0
I
CCON
(mA)
Supply Current (On) versus Supply Voltage
5.0
4.0
V
CC
(V)
24
3.6
3.0
2.0
1.0
0
T
A
(°C)
–40
25
150
I
CCON
(mA)
3.0
2.0
1.0
0.0
-50
0
50
T
A
(°C)
100
150
0
5
10
V
CC
(V)
15
20
25
Supply Current (Off) versus Ambient Temperature
5.0
4.0
I
CCOFF
(mA)
Supply Current (Off) versus Supply Voltage
5.0
4.0
V
CC
(V)
24
3.6
3.0
2.0
1.0
0
T
A
(°C)
-40°C
–40
25°C
25
150°C
150
I
CCOFF
(mA)
3.0
2.0
1.0
0.0
-50
0
50
T
A
(°C)
100
150
0
5
10
V
CC
(V)
15
20
25
Output Voltage (On) versus Ambient Temperature
500
450
400
V
OUT(SAT)
(mV)
Output Voltage (On) versus Supply Voltage
500
450
400
V
CC
(V)
24
3.6
V
OUT(SAT)
(mV)
350
300
250
200
150
100
50
0
-50
0
50
T
A
(°C)
100
150
350
300
250
200
150
100
50
0
0
5
10
V
CC
(V)
15
20
25
T
A
(°C)
150°C
–40
25°C
25
-40°C
150
Continued on the next page...
A3241-DS, Rev. 2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
4
A3241 and A3242
Chopper-Stabilized Unipolar Hall Effect Switches
Operate Point versus Ambient Temperature
(A3241)
130
120
110
B
OP
(G)
B
OP
(G)
Operate Point versus Supply Voltage
(A3241)
130
120
110
V
CC
(V)
24
3.6
100
90
80
70
60
50
T
A
(°C)
–40
25
150
100
90
80
70
60
50
-50
0
50
T
A
(°C)
100
150
0
5
10
V
CC
(V)
15
20
25
110
100
90
B
RP
[G]
Release Point versus Ambient Temperature
(A3241)
Release Point versus Supply Voltage
(A3241)
110
100
90
V
CC
(V)
24
3.6
B
RP
(G)
80
70
60
50
40
-50
0
50
T
A
(°C)
100
150
80
70
60
50
40
0
5
10
V
CC
(V)
15
20
25
T
A
(°C)
–40
25
150
Hysteresis versus Ambient Temperature
(A3241)
40
35
B
HYS
(G)
B
HYS
(G)
Hysteresis versus Supply Voltage
(A3241)
40
35
V
CC
(V)
24
3.6
30
25
20
15
10
T
A
(°C)
–40
25
150
30
25
20
15
10
-50
0
50
T
A
(°C)
100
150
0
5
10
V
CC
(V)
15
20
25
A3241-DS, Rev. 2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
5
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