Infineon has recently introduced the PASCO2V15, a new 5 V sensor to improve air quality monitoring in building environments.
New Xensiv PAS CO2 sensor. Image (modified) used courtesy of Infineon
Indoor air quality has become a focal point across multiple industries, especially as concerns about environmental health and energy efficiency grow. Buildings, both residential and commercial, are increasingly integrating smart technologies to monitor and maintain optimal conditions. Carbon dioxide (CO2) levels, in particular, are a major indicator of air quality that can potentially affect cognitive function and general health.
Infineon’s PASCO2V15 is a compact carbon dioxide sensor based on photoacoustic spectroscopy (PAS), which enables highly accurate gas detection.
Infineon Unveils Compact PAS CO2 Sensor
The PASCO2V15 (datasheet linked) architecture incorporates MEMS microphones and infrared (IR) light sources, where CO2 molecules absorb the IR radiation. This absorption generates tiny pressure changes within the sensor chamber, which the integrated acoustic MEMS detects. This design minimizes the need for optical components, enhancing stability and reducing the overall footprint to 13.8 mm x 14 mm x 7.5 mm.
Block diagram of PASCO2V15. Image used courtesy of Infineon
With this architecture, the sensor achieves a high level of precision, offering an accuracy of ±50 ppm ±5% between 400 ppm and 3,000 ppm. The overall range of the sensor is from 0 to 32,000 ppm.
The sensor also features pressure compensation capabilities to correct CO2 readings based on atmospheric pressure variations. It supports automatic baseline offset correction (ABOC) to compensate for long-term drifts caused by aging. The device can also perform forced compensation for faster recalibration.
For power supply, the PASCO2V15 requires 5 V for the IR emitter and 3.3 V for digital components, with a peak current of 290 mA at 5 V and 10 mA at 3.3 V. It features a typical response time of 55 seconds and operates in three modes: idle, single-shot, and continuous. In continuous mode, the device can be programmed for a measurement interval between 5 seconds and 4,095 seconds. The sensor consumes an average of 30 mW when performing one measurement per minute,
What Is PAS?
Photoacoustic spectroscopy is a gas detection method that leverages the photoacoustic effect, where gas molecules absorb light and convert it into acoustic waves.
PAS works by shining modulated infrared light into a chamber containing the target gas—in this case, carbon dioxide. When the gas absorbs the IR radiation, the energy is converted into heat, causing periodic pressure fluctuations. These pressure changes generate acoustic waves detected by highly sensitive microphones, typically based on MEMS. By analyzing the acoustic signal, users can accurately determine the gas concentration.
Components of a photoacoustic spectrometer. Image used courtesy of Chemistry LiibreTexts
Unlike non-dispersive infrared (NDIR) sensors, which rely on optical detection of light absorption, PAS directly measures the acoustic signal generated by gas absorption. This eliminates the need for optical components like mirrors and detectors, significantly reducing the size and complexity of the sensor. As a result, PAS-based sensors can be made more compact and are less prone to drift or alignment issues, improving long-term reliability. Additionally, PAS offers excellent sensitivity even in low-concentration environments, making it suitable for applications like indoor air quality monitoring or industrial gas sensing.
CO2 Sensing for Smarter Buildings
As more industries prioritize indoor environmental quality, integrating sensors like the PASCO2V15 could reshape how buildings monitor air quality in real time, enabling smarter automation of ventilation systems and energy management.
