The STC31-C from Sensirion is an advanced gas concentration sensor designed for precise measurement of high-range carbon dioxide (CO₂) concentrations. Engineered for demanding environments, it is particularly well-suited for high-volume applications such as the transportation and storage of perishable goods, pharmaceutical logistics, and breath analysis systems for monitoring CO₂ levels in human respiration.
At the core of the STC31-C lies a revolutionary thermal conductivity measurement principle, delivering exceptional repeatability and long-term stability. This innovative approach ensures unmatched reliability, making the STC31-C the ideal choice for mission-critical applications where accuracy and consistency are paramount. Unlike traditional optical sensors, thermal conductivity technology offers ultra-low power consumption, making it perfect for battery-operated devices that require top-tier performance with minimal energy usage.
Housed in a compact QFN12 package measuring just 3.5 × 3 × 1 mm, the STC31-C provides fully calibrated digital outputs for both gas concentration and temperature. The sensor provides accurate and reliable measurements and features low power consumption and low cross-sensitivity to humidity and oxygen changes.
The STC31-C sensor can measure CO₂ concentrations from 0-100 vol% with an accuracy of ±(0.2 - 2.0 vol%) and temperature stability of 0.02 vol%/°C. The sensor has a supply voltage range from 2.7 to 5.5V and average supply current of 50 µA.
Building on the proven performance of its predecessor, the STC31, the STC31-C introduces a low-cross-sensitivity measurement mode, significantly reducing the influence of humidity and oxygen fluctuations. This enhancement makes it particularly suitable for breath analysis applications, while retaining all the core benefits of the original STC31.
Functional Block Diagram
The STC31-C sensor features a digital I²C interface, enabling seamless integration with microprocessors. Its outstanding performance is powered by Sensirion's patented CMOSens® Technology, which combines the sensing element, signal processing, and digital calibration on a single CMOS chip. This proven technology ensures high-quality mass production, making the STC31-C an excellent choice for high-quality mass production and is the ideal choice for demanding and cost-sensitive OEM applications.
Recommended Application Circuit
The STC31-C offers two measurement modes:
Low-cross-sensitivity (recommended standard measurement mode), in this measurement mode, the influence of humidity, temperature, pressure, and oxygen on the CO₂ measurement is significantly reduced. Therefore, the low-cross-sensitivity mode is recommended in most cases. It offers a sample frequency of up to 7Hz and the physical response time to gas change is identical to the low-noise mode.
Low-noise, this mode has the advantage of a slightly faster sampling rate (10Hz) and a lower measurement noise but shows significant cross-sensitivities to humidity, temperature, pressure, and oxygen and is therefore not recommended for most use cases. The communication interface for this mode is kept identical to the predecessor sensor STC31 (NRND Mai 2024) for backward compatibility.
To support developers and accelerate adoption, Sensirion offers the SEK-STC31-C Evaluation Kit which jumpstarts the sensor assessment process by offering a straightforward testing approach. Featuring integrated STC31-C and SHTC3 (Humidity & Temperature) sensors on a development board, the kit enables fast and flexible testing of the sensor for various applications.
Kit Contents: 1× STC31-C 1× SHTC3 on FPCB 1× RJ45 adapter cable (1 meter length)
Designed for seamless integration with the SEK-SensorBridge the kit allows up to two evaluation boards to connect to a computer via USB, enabling fast and flexible testing. Sensirion complements this with a robust software platform and driver support, making sensor evaluation straightforward and efficient.
The STC31-C is suitable for a range of applications, including Transportation, Food & perishable goods storage, Pharmaceutical, Breath analysers, Instrumentation equipment and much more.
Experience next-generation CO₂ sensing with Sensirion's STC31-C, combining cutting-edge thermal conductivity technology and CMOSens® innovation for unmatched accuracy and performance.
Anglia are offering customers a FREE evaluation kit and samples of the STC31-C High Volume CO₂ sensor from Sensirion, please fill in the form below to register your interest now.
Free samples are subject to availability.
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