Compact & cost-effective photoacoustic NDIR CO₂ sensor
The SCD40 represents the base variant in the SCD4x series and provides a cost-effective photoacoustic NDIR CO2 sensor delivering an accuracy of ±(50ppm + 5% m.v.) between 400 and 2000 ppm. The sensor is compatible with the WELL Building Standard™.
The SCD4x is Sensirion’s second generation series of optical CO2 sensors. The sensor series builds on the photoacoustic NDIR sensing principle and Sensirion’s patented PASens® and CMOSens® technology to offer accuracy at an attractive price and small form factor. SMD assembly allows cost- and space-effective integration of the sensor combined with maximal freedom of design. On-chip signal compensation is realized with the built-in SHT4x humidity and temperature sensor. Tape and reel packaging make the SCD4x ideal for high-volume applications.
Carbon dioxide is a key indicator for indoor air quality (IAQ), as high levels compromise human cognitive performance and well-being. The SCD4x enables smart ventilation regulation to help improve energy efficiency and human comfort. Moreover, indoor air quality monitors and other connected devices based on the SCD4x can help maintain low CO2 concentrations for a healthy, productive environment.
| CO₂ | |||
|---|---|---|---|
| CO₂ Output Range0 - 40000ppm | 0 - 40000 | ppm | |
| Specified CO₂ Measurement Range400 - 2000ppm | 400 - 2000 | ppm | |
| Accuracy±50.0 ppm ±5.0 %m.v. | ±50.0 ppm ±5.0 %m.v. | ||
| Response time (τ63%)60s | 60 | s |
| Humidity | |||
|---|---|---|---|
| Typ. relative humidity accuracy6%RH | 6 | %RH | |
| Operating relative humidity range0 - 95%RH | 0 - 95 | %RH | |
| Response time (τ63%)90s | 90 | s | |
| Calibration certificateFactory calibration | Factory calibration |
| Generic | |||
|---|---|---|---|
| Supply voltage2.4 - 5.5V | 2.4 - 5.5 | V | |
| Average supply current15mA | 15 | mA | |
| Max. supply current205mA | 205 | mA | |
| Operating temperature range [°C]-10 - 60°C | -10 - 60 | °C | |
| InterfacesI²C |

Sensirion's sensor solutions are used in a wide range of applications and markets. Our reliable environmental and flow sensors improve energy efficiency, increase health and ensure safety and comfort.
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| Size (LxWxH)10.1 x 10.1 x 6.5mm | 10.1 x 10.1 x 6.5 | mm |
| Packaging size60 and 600pcs (T&R) | 60 and 600 | pcs (T&R) |
| Temperature | |||
|---|---|---|---|
| Typ. temperature accuracy0.8°C | 0.8 | °C | |
| Response time (τ63%)120s | 120 | s |