The A3507 and A3508 are sensitive, temperature-stable linear
Hall-effect sensors. Ratiometric, linear Hall-effect sensors provide a
voltage output that is proportional to the applied magnetic field and have
a quiescent output voltage that is approximately 50% of the supply
voltage. These magnetic sensors are ideal for use in linear and rotary
position sensing systems in the harsh environments of automotive and
industrial applications over extended temperatures to -40
C and +150C.
The two devices are similar except for temperature stability over the
operating temperature range. See the Magnetic Characteristics table for
complete, individual device parametrics.
Each monolithic circuit integrates a quadratic Hall element, im-
proved temperature compensating circuitry to reduce the intrinsic
sensitivity drift of the Hall element, a small-signal high-gain amplifier,
and a rail-to-rail low-impedance output stage. Many problems normally
associated with low-level analog signals are minimized by having the
Hall element and amplifier in a single chip. Output precision is obtained
by internal gain and offset trim adjustments during the manufacturing
process.
The first character of the part number suffix determines the device
operating temperature range: suffix `S' is for -20
C to +85
C, suffix
`E' is for -40
C to +85
C, and suffix `L' is for -40
C to +150
C.
These devices are supplied in a 3-pin ultra-mini-SIP `UA' package.
FEATURES
I Output Voltage Proportional to Applied Magnetic Field
I Ratiometric Rail-to-Rail Output
I Improved Sensitivity
I Superior Temperature Stability
I 4.5 V to 5.5 V Operation
I Small Package Size
I Solid-State Reliability
RATIOMETRIC, LINEAR HALL-EFFECT SENSORS
FOR HIGH-TEMPERATURE OPERATION
Data Sheet
27501.1B
3507
AND
3508
Always order by complete part number, e.g., A3507EUA .
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
. . . . . . . . . . . . 6.0 V
Output Voltage, V
O
. . . . . . . . . . . . . 6.0 V
Output Sink Current, I
O
. . . . . . . . 5.0 mA
Magnetic Flux Density, B . . . . Unlimited
Package Power Dissipation,
P
D
. . . . . . . . . . . . . . . . . . . . See Graph
Operating Temperature Range, T
A
Suffix `S' . . . . . . . . . . . . -20
C to +85
C
Suffix `E' . . . . . . . . . . . . -40
C to +85
C
Suffix `L' . . . . . . . . . . . -40
C to +150
C
Storage Temperature Range,
T
S
. . . . . . . . . . . . . . . -65
C to +170
C
Dwg. PH-006
1
SUPPLY
V
CC
GROUND
3
2
OUTPUT
X
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3507
AND
3508
RATIOMETRIC,
LINEAR HALL-EFFECT SENSORS
FOR HIGH-TEMP. OPERATION
600
400
200
20
60
100
140
0
AMBIENT TEMPERATURE in
C
ALLOWABLE PACKAGE POWER DISSIPATION in MILLIWATTS
Dwg. GH-046A
"U" PACKAGE
R
JA
= 183
C/W
"UA" PACKAGE
R
JA
= 206
C/W
40
80
120
160
700
500
300
100
V
CC
X
Dwg. FH-011
GROUND
2
OUTPUT
3
1
Copyright 1994, 2000, Allegro MicroSystems, Inc.
ELECTRICAL CHARACTERISTICS
over operating temperature range, at V
CC
= 5 V (unless otherwise
noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Supply Voltage
V
CC
Operating
4.5
5.0
5.5
V
Supply Current
I
CC
B = 0, V
CC
= 5.5 V, I
O
= 0
10
mA
Quiescent
V
OQ
B = 0, I
O
= 1 mA, T
A
= 25
C
2.0
2.5
3.0
V
Voltage Output
B = 0, I
O
= 1 mA
1.8
2.5
3.2
V
Output Voltage
V
OH
B = +X
*
, I
O
= 1 mA
4.5
4.8
V
V
OL
B = -X
*
, I
O
= -1 mA
0.2
0.5
V
Bandwidth (-3 dB)
BW
20
kHz
Output Resistance
r
O
2.5
10
Wide-Band
e
o
B = 0, BW = 10 Hz to 10 kHz,
125
V
Output Noise
T
A
= 25
C
Negative current is defined as coming out of (sourcing) the output.
* This test requires positive and negative fields sufficient to swing the output driver between fully OFF and saturated (ON), respec-
tively. It is NOT intended to indicate a range of linear operation.
FUNCTIONAL BLOCK DIAGRAM
3507
AND
3508
RATIOMETRIC,
LINEAR HALL-EFFECT SENSORS
FOR HIGH-TEMP. OPERATION
www.allegromicro.com
MAGNETIC CHARACTERISTICS
over operating temperature range, at V
CC
= 5 V, I
O
= 1 mA
(unless otherwise noted).
Part Numbers
A3507LUA
A3507EUA
A3508SUA
Characteristic
*
Min.
Typ.
Max.
Min.
Typ.
Max.
Min.
Typ.
Max.
Units
Operating Temp. Range, T
A
-40
+150
-40
+85
-20
+85
C
Sensitivity
at T
A
= 25
C
2.0
2.5
3.0
2.0
2.5
3.0
2.0
2.5
3.0
mV/G
over Oper. Temp. Range
1.7
2.5
3.3
1.7
2.5
3.3
1.7
2.5
3.3
mV/G
Sens
(
T)
at T
A
= Max.
-5.0
2.5
10
-6.3
1.2
8.7
-10
10
%
at T
A
= Min.
-8.8
-1.3
6.2
-8.8
-1.3
6.2
-10
10
%
V
OQ(
T)
35
35
50
G
Ratiometry,
V
OQ(
V)
100
100
100
%
Ratiometry,
Sens
(
V)
100
100
100
%
Positive Linearity, Lin+
100
100
100
%
Negative Linearity, Lin
100
100
100
%
Symmetry
100
100
100
%
Magnetic flux density is measured at most sensitive area of device located 0.018" (0.46 mm) below the branded face of the "UA"
package.
* See Characteristics Definitions for test conditions.
The nominal sensitivity temperature stability is designed to compensate for the temperature coefficient of samarium-cobalt
magnets (-0.02%/
C).
This calculation (formula 1, next page) yields the device's equivalent accuracy, over the operating temperature range, in gauss.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3507
AND
3508
RATIOMETRIC,
LINEAR HALL-EFFECT SENSORS
FOR HIGH-TEMP. OPERATION
CHARACTERISTICS DEFINITIONS
Ratiometry. The A3507 and A3508 feature a ratiometric
output. The quiescent voltage output and sensitivity are
proportional to the supply voltage (ratiometric).
The per cent ratiometric change in the quiescent voltage
output is defined as
V
OQ(
V)
=
V
OQ(VCC)
/ V
OQ(5V)
x 100%
(4)
V
CC
/ 5 V
and the per cent ratiometric change in sensitivity is defined as
Sens
(
V)
=
Sens
(VCC)
/ Sens
(5V)
x 100%
(5)
V
CC
/ 5 V
Linearity and Symmetry. The on-chip output stage is de-
signed to provide a linear output to within 500 mV of either rail
with a supply voltage of 5 V. This is equivalent to approxi-
mately
800 gauss of ambient field. Although application of
stronger magnetic fields will not damage these devices, it will
force the output into a non-linear region. Linearity in per cent
is measured and defined as
Lin+ =
V
O(500G)
V
OQ
x 100%
(6)
2 (V
O(250G)
V
OQ
)
Lin =
V
O(-500G)
V
OQ
x 100%
(7)
2 (V
O(-250G)
V
OQ
)
and output symmetry as
Sym =
V
O(500G)
V
OQ
x 100%
(8)
V
OQ
V
O(-500G)
Quiescent Voltage Output. In the quiescent state (no mag-
netic field), the output is ideally equal to one-half of the supply
voltage over the operating voltage and temperature range (V
OQ
V
CC
/2). Due to internal component tolerances and thermal
considerations, there is a tolerance on the quiescent voltage
output and on the quiescent voltage output as a function of
supply voltage and ambient temperature. For purposes of
specification, the quiescent voltage output as a function of
temperature is defined as
V
OQ(
T)
=
V
OQ(TA)
V
OQ(25
C)
(1)
Sens
(25
C)
This calculation yields the device's equivalent accuracy,
over the operating temperature range, in gauss.
Sensitivity. The presence of a south-pole magnetic field
perpendicular to the package face (the branded surface) will
increase the output voltage from its quiescent value toward the
supply voltage rail by an amount proportional to the magnetic
field applied. Conversely, the application of a north pole will
decrease the output voltage from its quiescent value. This
proportionality is specified as the sensitivity of the device and
is defined as
Sens =
V
O(500G)
V
O(-500G)
(2)
1000 G
The stability of sensitivity as a function of temperature is
defined as
Sens
(
T)
=
Sens
(TA)
Sens
(25
C)
x 100%
(3)
Sens
(25
C)
3507
AND
3508
RATIOMETRIC,
LINEAR HALL-EFFECT SENSORS
FOR HIGH-TEMP. OPERATION
www.allegromicro.com
SENSOR LOCATION
APPLICATIONS INFORMATION
Calibrated linear Hall devices, which can be used to
determine the actual flux density presented to the sensor in a
particular application, are available.
For safe, reliable operation, the output should not be
pulled above the supply voltage or pulled below the device
ground.
For optimum performance, a 100 pF capacitor between
the output and ground should be added.
The nominal sensitivity is factory set to compensate for
the temperature coefficient of samarium-cobalt magnets
(-0.02%/
C).
The ratiometric feature is especially valuable when these
devices are used with an analog-to-digital converter. A/D
converters typically derive their LSB step size by ratioing off a
reference voltage line. If the reference voltage varies, the LSB
will vary proportionally. This is a major error source in many
sensing systems. The A3507/08 can eliminate this source of
error by their ratiometric operation. Because their gain and
offsets are proportional to the supply voltage, if they are
powered from the A/D reference voltage, the sensor output
voltage will track changes in the LSB value.
Hall-effect applications information is available in the
application note "Linear Hall-Effect Sensors" (AN 27702),
which can be found in the latest issue of Allegro Electronic
Data Book, AMS-702, or at
www.allegromicro.com
1
3
2
Dwg. MH-011-6A
0.018"
0.46 mm
NOM
BRANDED
SURFACE
ACTIVE AREA DEPTH
0.082"
2.07 mm
0.055"
1.40 mm
A
B
N x 6.9 G/A
Dwg. AH-005A
TYPICAL CURRENT-SENSING APPLICATION
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