Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 1 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Features
The thermopile sensor consists of a series of 44 thermoelements, forming a sensitive area of
0.5*0.5 mm2. The sensor is hermetically sealed into a TO-5 metal housing, with an optical filter.
This standard filter allows measurements to be made in the spectral range above 5m wavelength.
The thermosensor exhibits an almost white noise, comparable to an ohmic resistance. It has a
constant signal versus frequency up to its frequency limit, and is directly proportional to incident
radiation. The thermopile sensors are featured with an additional temperature reference resistor on
the same chip. The standard version of temperature reference resistor is housing connected to
ground.
Applications
* Ear thermometers; clinic thermometers
* Infrared thermometers
* Consumer applications: hair dryer, micro-wave oven, air conditioner, refrigerator
* Continuous temperature control of manufacturing
* Security system
* Radiation monitor switch system
* Absorbing measurement for gas analysis
* Thermoelectric converter
* Heat flux flowmeter
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 2 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Electrical Characteristics
Parameter Condition Min. Typ. Max. Unit
Thermopile
Number of thermojunctions --- 44 ---
Chip size --- 1920*1725 --- m2
Active area Interference
layer --- 500*500 --- m2
Thickness of substrate Silicon-
substrate 600 625 650 m
Resistance of thermopile 2560 70 80 K
Sensitivity With 5-14m
filter 40 55 70 V/W
Detecctivity 4*1077*1079*107cm*Hz1/2/W
Time constant --- 30 --- ms
Noise voltage --- 34 --- nV/Hz1/2
NEP --- 0.8 --- nW/Hz1/2
Temperature range Operation -20 --- 100
Temperature reference res istor ---
Resistance 25920 1000 1080
Temperature coefficient of resistance 253470 3700 3920 ppm/K
Measured at 1 Hz chopper frequency, within spectral range 5-14m, using a blackbody radiator of
500K temperature.
Note : Thermistor should be operated under 200A.
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 3 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Thermopile voltage vs. blackbody temperature
Frequency response
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 4 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Field of view
1) window size: 2.57mm (diameter)
2) window size: 3.80mm (diameter)
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 5 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Thermistor vs. temperature
The resistance of the temperature reference resistor varies with temperature and the behaviour is
illustrated in the following figure.
At temperature 25, the relation R = Ro[(1+(T-To)+(T-To)2)] is almost linear, where the typical
value of is 3.6*10-6 << 1 and(temperature co-efficient of resistance) is 3.7*10-3 defined as :
=
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 6 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Pin assignment & description
2 thermistor pin
4 thermistor pin (GND)
1 thermopile output pin (+)
3 thermopile output pin (-)
Order information : OTC-236-AB
A : 1 : standard filter (5-14m)
2 : silicon filter with flat band transmission
3 : band pass filter
B : 1 : window size = 2.57mm (diameter)
2 : window size = 3.80mm (diameter)
Thermistor Thermopile
2(R) 3(V-)
1(V+) 4(GND)
BACKSIDE VIEW SIDE VIEW
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 7 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Transmission of filter
Transmission of optical filter is measured by FTIR from 2m
Package
The sensor is hermetically sealed into a TO-5 metal housing, with an optical filter. This standard
filter allows measurements to be made in the spectral range above 5m wavelength. The
dimensions of header and cap are shown below.
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 8 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
OTC-236-11
OTC-236-12
Cap
Header
4.3
2.00
Unit: mm
4.6
Chip
Window
IR
filter
ψ3.80
ψ8.17
Unit: mm
2.0
0.43
4.6
Chip
Cap
Header
Window
IR
filter
ψ2.57
ψ5.0
ψ8.15
Window
IR Filter
IR Filter
WIindow
Thermopile Infrared Sensor OTC-236
Microelectronics Dept. 2000.01 9 / 9
OPTO TECH CORPORATION
Tel: 886-3-5777481
Fax: 886-3-5783696
http://www.opto.com.tw
OPTO TECH
Application circuit
Circuit 1 :
Circuit 2 :
C1 R1
C2
R2
2
4
R4
R3
+
-
1
3
C3
C4
R5 R6
+
OP
-
C6
C5
Vout
+5V
Reference
Resistor
Thermopile
R2
+5V
+
A1
-
+
A3
-
+
A2
-
+
-
Adder
Vout
C3
R9
R8
C2
Thermopile (-)
Thermopile (+)
R1
R7
C1
2
4
R13
R10
R11
R12
+5V
C4
reference
resistor
Ambient Temperature
Compensation Circuit
Pre-Amplification Circuit
1
3
