SMARTEC B.V.
Infrared sensor type: SMTIR9901/9902
Version : 3.1
Date : jan 2003
1
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1
Introduction
The Smartec infrared sensor SMTIR9901 and SMTIR9902 are sophisticated full
silicon infrared sensors. The sensors can be used in measuring the radiation
temperature without any contact. For the different radiation temperature ranges various
filters are available. The sensor type SMTIR9902 contains a temperature sensor for
measuring the temperature of the sensor itself. The temperature range of the sensor-
element is between - 40 to 100 C. The sensor is available in a standard TO-05
encapsulation and with a 5.5.
m high pass filter.
2
Typical applications
Contactless measurement of surface temperatures or Infrared radiation
temperature measurement on moving objects.
Continuous temperature control of manufacturing.
Thermal alarmsystems
Climate control
Medical instruments
Home appliances.
Easy and accurate measuring of the sensors temperature by means of a built-in
temperature sensor(only for type SMTIR9902).
The main characteristics of the infrared sensor are:
High accuracy
High sensitivity (110 V/W)
Low resistance (50 K
) and therefore
Very good signal-to-noise-ratio
Good response time (40 ms)
Low cost thin film technology
3
Pin-out and housing (TO 5)
Sensor surface
All sizes in mm.
Bottom view
8.15
3.9
4.4
1.8
5.1
8
1
2
3
4
SMTIR9902
1 = det -
2 = det +
3 = NI1000
4 = NI1000
SMTIR9901
1 = det -
2 = det +
3 = N.C.
4 = GND
SMARTEC B.V.
Infrared sensor type: SMTIR9901/9902
Version : 3.1
Date : jan 2003
2
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Product description.
Thermopiles are based on the Seebeck effect, which can be considered ever since a
long time as standard for conventional thermocouples.The application of thin film
technology allows the production of miniaturized and low cost sensor elements.
A series connection of thermojunctions deposited on a silicon substrate forms the
thermopile. The hot junctions are thermally isolated from the cold junctions on the
substrate by etching an extremely thin membrane. A black absorbing layer on the hot
junctions transform the incoming radiation into heat. A voltage proportional to the
radiation is generated by the thermoelectric effect.
The used thermopiles are processed on 400
m silicon substrates using BiSb and NiCr
for the thermojunctions.
For different radiation spectra various filters are available to find the optimal solution.
5 Specifications
Parameters
typical
units
Number of thermojunctions
100
Active area
0.50
mm
Die size
2.2 * 2.2
mm
Resistance of thermopile
50 15
K
Sensitivity
110 20
V/W 1)
Temp coeff of sensitivity
-0.52 0.08
%/K
Specific Detectivity
2.1 * 10e8
cm.Hz/W 1)
Noise equivalent power
0.35
nW 1)
Noise Voltage
37
nV/Hz
Time constant
40 10
ms (63 %)
Temperature range (sensor)
-20 - 100
C
Storage temperature
-40 - 100
C
Filter (high Pass)
5.5
m
1) at 500 K,DC
Reference thermistor (SMTIR9902 only)
Resistance
1.000 0.004
K
( @ 0C)
SMARTEC B.V.
Infrared sensor type: SMTIR9901/9902
Version : 3.1
Date : jan 2003
3
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FILTER (characteristic)
6 Understanding the specifications
Sensitive area
.
The sensitive area is a square of .5 mm. By using the distance between the sensor
element and the glass filter and its diameter the field of view can be determined. The
field of view can be changed by using special lenses. In case lenses are used the
emissivity and the spectrum has to be considered.
Filter.
The sensors are standardwise equipped with a high pass filter. From the theory it is
well known that each body has a radiation at a certain temperature. This radiation
temperature has a frequency related to that temperature. For general use the filter used
is a high pass filter with a cut-off wavelength of 5.5 m.
Sensor resistance
.
It must be clear that this type of thermopile has a reasonable output resistance. This
resistance has to be considered when designing the input amplifier to prevent off-setts,
etc.
Time constant
.
The time constant is the time needed to reach an output voltage of 66 % of the final
level. This time constant only depends on the physical construction.
0
10
20
30
40
50
60
70
80
90
100
4
5
6
7
8
9 10 11 12 13 14 15
wavelength(micrometer)
%
SMARTEC B.V.
Infrared sensor type: SMTIR9901/9902
Version : 3.1
Date : jan 2003
4
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Temperature reference resistor(SMTIR9902).
It is well known that for application on a infrared sensor the temperature of the sensor
must be considered in the calculation of the radiation temperature. The used resistor
Is a standard Ni resistor with a value of 1000
@ 0 C.
The relation between the resistance value and the temperature is given below:
R(T)=R0*(1+A*T+B*T
2
+C*T
4
+D*T
6
) tolerance class B
R0= resistance @ 0C = 1000
T = Temperature in C
A = 5.485 * 10
-3
B = 6.650 * 10
-6
C = 2.805 * 10
-11
D = -2.000 * 10
-17
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Ordering information
SMTIR9901 Infraredsensor without temperature sensor
SMTIR9902 Infraredsensor with temperature sensor
For more information and or samples:
SMARTEC BV
Delpratsingel 26
4811 AP BREDA
The Netherlands
Tel: * 31 76 520 5353
Fax: * 31 76 520 5354
Email:
SMARTECNL@CS.COM
URL:
WWW.SMARTEC.NL
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