Giant Magneto Resistive Position Sensor
Version 2.0
GMR B6
This angle sensor is based on the Giant Magneto Resistive (GMR) technology.
It is outstanding for the huge tolerances it offers to the user in assembly.
2.6 max
10˚ max
Features
• GMR sensor in SMD package
•
Sensitive to the direction,
not to the intensity of the
magnetic field
• Constant
T
C
of basic
resistance
R
and magneto
resistance
∆
R
Applications
• Rotation and linear sensing
with large airgaps
• Angle encoders
• Contactless potentiometers
• Incremental encoders
Pin Configuration
6
3
B
2.9
±0.1
1.9
0.6
+0.1
-0.05
6
5
4
2˚ ... 30˚
1.1 max
0.08 ... 0.15
0.1
±0.3
A
10˚ max
0.1 max
M
1
2
3
0.2
0.35
±0.15
+0.1
0.3
-0.05
0.25
M
B
0.20
A
Reflow soldering
0.8
0.3
1
4
R
1
R
3
0.5
0.45
OHS00429
0.9
R
2
R
4
1.2
3
Directions of internal
magnetization
GPW06957
2/5
Dimensions in mm
6, 3
5 (= 2)
1, 4
Type
GMR B6
supply
ground
GMR bridge access
Marking
B
Ordering Code
Q62705-K5004
Data Sheet
1
2000-07-01
1.3
±0.1
GMR B6
The GMR B6 is an angle sensor based on sputtered metallic multilayer technology.
4 resistors are monolithically integrated on 1 chip. They can be used as a fullbridge or,
if 2 external resistors are added, as 2 halfbridges. The outstanding feature of this
magnetic sensor is the fact, that it is sensitive to the orientation of the magnetic field and
not to its intensity as long as the field is in a range between 5 … 15 kA/m. This means,
the signal output of this sensor is independent of the sensor position relative to the
magnet in lateral, axial or rotational direction in the range of several millimeters.
Optimum results are achieved by using magnetic targets like permanent magnets or
magnetic pole-wheels. There is no need for a biasing magnet! Due to the linear change
of both, basic and field dependent part of the resistance vs. temperature, simple and
efficient electronic compensation of
T
C
(
R
,
∆
R
) is possible.
1
AED02956
∆R
)/2
]
R
O
Bridge Voltage
[
(
V
O
∗
N
0.5
Figure 1
Output Voltage of Half Bridges (V1, V4) and Full Bridge (V4 - V1) as a Function of
the Magnetic Field Orientation
Data Sheet
S
GMR B6
V
4
0
V
1
-0.5
V
1
-
V
4
-1
0
90
180
270
Angle
Deg
360
2
2000-07-01
GMR B6
Maximum Ratings
Parameter
Operating temperature
Storage temperature
Supply voltage
Thermal conductivity
Magnetic field
1)
1)
Symbol
Value
– 40 … + 150
– 50 … + 150
7
>4
< 15
Unit
°C
°C
V
mW/K
kA/m
T
A
T
stg
V
1
G
thC
A
H
rot
larger fields may reduce the magnetoresistive effect irreversibly
Characteristics (
T
A
= 25
°C)
Parameter
Nominal supply voltage
Basic resistance
Magnetoresistive effect
H
rot
= 5 ... 15 kA/m
Output signal fullbridge
Offset voltage
Temperature coefficient of
basic resistance
Temperature coefficient of
magnetoresistance
Temperature coefficient of
magnetoresistive effect
Application Hints
The application mode of the GMR position sensor is preferably as a bridge or halfbridge
circuit. In every case this type of circuit compensates for the
T
C
of the resistance value
R
0
. To compensate for the
T
C
of the GMR effect
∆
R
/
R
0
, if there is the necessity, is left to
the application circuit and can be done for example with a NIC circuit. When operated
over a complete 360° turn, a total signal of
≈
20 mV/V is achieved at 25
°C
with a
halfbridge. The output signal is doubled to of
≈
40 mV/V when a fullbridge circuit is used.
In the case of linear position sensing, the electrical circuit remains unchanged.
Symbol
Value
5
> 700
>4
> 200
<8
+ 0.09 … + 0.12
– 0.12 … – 0.09
– 0.27 … – 0.23
Unit
V
Ω
%
mV
mV
%/K
%/K
%/K
V
1N
R
0
∆
R
/
R
0
@
V
1N
= 5 V
V
OUT
@
V
1N
= 5 V |
V
0
|
TC
R0
TC
∆R
TC
∆R/R0
Data Sheet
3
2000-07-01
GMR B6
Output Voltage Degradation (typical) at
high Temperature Operation
100
%
99
AED02953
Magnetoresistive Effect (typical) versus
Temperature
∆
R
/
R
0
=
f
(
T
A
)
120
%
110
Magnetoresistive Effect (normalized)
AED02959
T
A
= 105 ˚C
T
A
= 125 ˚C
Output Voltage (normalized)
100
98
90
97
80
96
70
T
A
= 150 ˚C
95
2
10
10
Operation Time
3
h 10
4
60
-50
-10
30
70
110 ˚C 150
T
Basic Resistance (typical) versus
Temperature
R
0
=
f
(
T
A
)
120
%
Resistance (normalized)
110
AED02954
100
90
80
-40 -20 0 20 40 60 80 100 ˚C 150
T
Data Sheet
4
2000-07-01
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