Semiconductor Group
1
07.96
The differential magnetoresistive sensor FP 212 L 100-22 consists of two series coupled
magneto resistors (L-type InSb/NiSb semiconductor resistors whose value can be
magnetically controlled) which are mounted onto an insulated ferrite substrate. The
sensor is encapsulated in a plastic package and has three connecting terminals.
The basic resistance of the total system is 2
100
. A permanent magnet which supplies
a biasing magnetic field is fixed on the base of the sensor.
Type
Ordering Code
FP 212 L 100-22
Q65212-L1004
Differential Magnetoresistive Sensor
FP 212 L 100-22
Dimensions in mm
Features
High output voltage
High operating temperature
Robust plastic housing
Biasing magnet build in
Signal amplitude is speed
independent
Marking silver
Typical applications
Detection of speed
Detection of position
Detection of sense of rotation
Angle encoder
Linear position sensing
Semiconductor Group
2
FP 212 L 100-22
Maximum ratings
Characteristics (
T
A
= 25
C)
Measuring arrangements
By approaching a soft iron part close to the sensor a change in its resistance is obtained.
The potential divider circuit of the magneto resistor causes a reduction in the
temperature dependence of the output voltage
V
OUT
.
Parameter
Symbol
Value
Unit
Operating temperature
T
A
40 / + 140
C
Storage temperature
T
stg
40 / + 150
C
Power dissipation
1)
P
tot
450
mW
Supply voltage
2)
V
IN
10
V
Insulation voltage between
terminals and magnet
V
I
> 60
V
Thermal conductivity
(when soldered)
G
thA
5
mW/K
Nominal supply voltage
V
IN N
5
V
Total resistance, (
=
,
I
1 mA)
R
1-3
220
...
400
Center symmetry
3)
(
=
)
M
10
%
Offset voltage
4)
(at
V
IN N
and
=
)
V
0
130
mV
Open circuit output voltage
5)
(
V
IN N
and
= 0.2 mm)
V
out pp
> 1000
mV
Cut-off frequency
f
c
> 20
kHz
1) Corresponding to diagram
P
tot
=
f
(
T
A
)
2) Corresponding to diagram
V
IN
=
f(T
A
)
3)
4) Corresponding to measuring circuit in Fig. 2
5) Corresponding to measuring circuit in Fig. 2 and arrangement as shown in Fig. 1
M
R
1
2
R
2
3
----------------------------
=
100% for
R
1-2
>
R
2-3
R
1
2
Semiconductor Group
3
FP 212 L 100-22
1. Digital revolution counting
For digital revolution counting, the sensor should be actuated by a magnetically soft iron
toothed wheel. The tooth spacing should correspond to about twice the magneto resistor
intercenter spacing i.e 2
1.6 mm (see Fig. 1).
The two resistors of the sensor are supplemented by two additional resistors in order to
obtain the sensor output voltage as a bridge voltage
V
OUT
. The output voltage
V
OUT
without excitation then is 0 V when the offset is compensated.
Fig. 1
Schematic representation of a toothed wheel actuating an FP 212 L 100-22
Fig. 2
Measuring circuit and output voltage
V
OUT
waveform
Semiconductor Group
4
FP 212 L 100-22
2. Linear distance measurement
To convert small distances into a proportional electric signal, a small soft iron part of
definite width (e.g.
b
= 1.8 mm) is moved over the face of the sensor.
Proportional signals for distances up to 1.5 mm can be obtained in this way. The
sinusoidal output signal gives a voltage proportional to distance in the zero crossover
region (see Fig. 3).
Fig. 3
Measuring arrangement for analogue application
Maximum supply voltage
versus temperature
V
IN
=
f
(
T
A
)
Semiconductor Group
5
FP 212 L 100-22
Output voltage (typical) versus
temperature
V
OUTpp
=
f
(
T
A
),
= 0.2 mm
V
OUTpp
at
T
A
= 25
C
100%
Total resistance (typical)
versus temperature
R
1-3
=
f
(
T
A
),
=
^
=
Output voltage (typical) versus
airgap
V
OUTpp
=
f
(
),
T
A
= 25
C
V
OUTpp
at
= 0.2 mm
100%
Max. power dissipation
versus temperature
P
tot
=
f
(
T
A
),
=
^
=
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