Infrared Sensors

The Smartec infrared sensors SMTIR99XX are sophisticated full silicon infrared sensors and comprise of so called thermopiles. Thermopiles are based on the Seebeck effect, which is a long time standard for conventional thermocouples. The application of thin film technology allows the production of miniaturised and low cost sensor elements. For specific applications there is a version with a small openings angle (7°).

The sensors can be used in measuring the radiation temperature without any contact. For 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 is standard wise equipped with a 5.5 micrometer filter. For a small field of view there is an infrared sensor available with a silicon lens.


The output voltage is generated by a thermopile, formed by a series connection of thermojunctions deposited on a silicon substrate. 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 silicon substrates using BiSb and NiCr for the thermojunctions. For different radiation spectra various filters are available to get the optimal solution.

Easy and accurate measuring of the sensor temperature can be done with a built-in temperature sensor (only for type SMTIR9902).

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
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Temperature Sensors

 Three terminal integrated temperature sensor

-Duty-cycle (PWM) output
-2.7 – 5.5 V power supply
–Analog voltage output with a low-pass filter
-Wide range of packaging possibilities
-Market proven excellent quality and stability
-Used in both:
High end market (medical and space industry) and
Low end market (consumer products)

The SMT172 is a three terminal integrated temperature sensor, with a duty-cycle output.

Two terminals are used for the power supply of 2.7 -5.5 Volts and the third terminal carries the output signal. A duty cycle modulated output is used because this output is interpretable by a microprocessor without A-D converter, while the analogue information is still available.

The sensors are available in a number of encapsulations: TO18, TO92, TO220, SOIC-8L, SOT223 and others. The temperature sensors are available as naked die as well. On request the sensors can also be built in customer specified encapsulations. For quick design-in a lot of application are available on the web and for plug and play we have designed Smart Temperature Acquisition System for 4 or 8 Smartec Temperature Sensors. It was designed to get the best possible temperature measurement results with the SMT172 Smartec temperature sensors (absolute accuracy 0.25 °C, noise <0.0004 °C), at little cost. With it, you don’t have to develop your own hardware application to connect 8 SMT172 temperature sensors to a PC. This board does it for you. On our website an application can be found to connect the board to an Excel or a simple labview application. In this way a low budget high accurate measurement system can be build.

The SMT172 has an overall accuracy of 0.1 °C in the range from -20 °C to +100 °C and an accuracy of 0.4 °C from -45 to +130 °C. This makes the sensor especially useful in all applications where “human” (climate control, food processing etc.) conditions are to be controlled.

The CMOS output of the sensor can handle cable length up to 20 meters. This makes the SMT172 very useful in remote sensing and control applications.

Reference: click here.

D&D Engineering – “W’ere YOUR Sensor Guys”
3835 E. Thousand Oaks Blvd. Suite 464 Westlake Village, CA 91362  – Voice: (818) 772-8720 Fax: (818) 772-2477 Toll Free: (888) 333-6474
Email: Website: