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SCD40

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.

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SCD40

SCD40-D-R2

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Specification

CO₂
CO₂ Output Range0 - 40000ppm0 - 40000ppm
Specified CO₂ Measurement Range400 - 2000ppm400 - 2000ppm
Accuracy
±50.0 ppm ±5.0 %m.v.
±50.0 ppm ±5.0 %m.v.
Response time (τ63%)60s60s
Humidity
Typ. relative humidity accuracy6%RH6%RH
Operating relative humidity range0 - 95%RH0 - 95%RH
Response time (τ63%)90s90s
Calibration certificateFactory calibrationFactory calibration
Generic
Supply voltage2.4 - 5.5V2.4 - 5.5V
Average supply current15mA15mA
Max. supply current205mA205mA
Operating temperature range [°C]-10 - 60°C-10 - 60°C
InterfacesI²C

Downloads

Datasheet SCD4x
  • 04/2025•
  • PDF•
  • 1.2 MB
DatasheetDownload Datasheet SCD4x04/2025Download Datasheet SCD4xPDFDownload Datasheet SCD4x1.2 MBDownload Datasheet SCD4x
Low power operation SCD4x
  • 07/2022•
  • PDF•
  • 443.0 KB
Application noteDownload Low power operation SCD4x07/2022Download Low power operation SCD4xPDFDownload Low power operation SCD4x443.0 KBDownload Low power operation SCD4x
Design-in guide SCD4x
  • 01/2021•
  • PDF•
  • 478.2 KB
GuideDownload Design-in guide SCD4x01/2021Download Design-in guide SCD4xPDFDownload Design-in guide SCD4x478.2 KBDownload Design-in guide SCD4x
Handling instructions SCD4x
  • 02/2025•
  • PDF•
  • 360.3 KB
GuideDownload Handling instructions SCD4x02/2025Download Handling instructions SCD4xPDFDownload Handling instructions SCD4x360.3 KBDownload Handling instructions SCD4x
Testing guide SCD4x
  • PDF•
  • 2.0 MB
GuideDownload Testing guide SCD4xDownload Testing guide SCD4xPDFDownload Testing guide SCD4x2.0 MBDownload Testing guide SCD4x
Arduino driver SCD4x
  • Link•
SoftwareDownload Arduino driver SCD4xDownload Arduino driver SCD4xLinkDownload Arduino driver SCD4xDownload Arduino driver SCD4x
Arduino snippets SCD4x
  • Link•
SoftwareDownload Arduino snippets SCD4xDownload Arduino snippets SCD4xLinkDownload Arduino snippets SCD4xDownload Arduino snippets SCD4x
BLE gadget SCD4x
  • Link•
SoftwareDownload BLE gadget SCD4xDownload BLE gadget SCD4xLinkDownload BLE gadget SCD4xDownload BLE gadget SCD4x
Embedded driver SCD4x
  • Link•
SoftwareDownload Embedded driver SCD4xDownload Embedded driver SCD4xLinkDownload Embedded driver SCD4xDownload Embedded driver SCD4x
Makecode for micro:bit SCD4x
  • Link•
SoftwareDownload Makecode for micro:bit SCD4xDownload Makecode for micro:bit SCD4xLinkDownload Makecode for micro:bit SCD4xDownload Makecode for micro:bit SCD4x
Python driver SCD4x
  • Link•
SoftwareDownload Python driver SCD4xDownload Python driver SCD4xLinkDownload Python driver SCD4xDownload Python driver SCD4x
Raspberry Pi driver SCD4x
  • Link•
SoftwareDownload Raspberry Pi driver SCD4xDownload Raspberry Pi driver SCD4xLinkDownload Raspberry Pi driver SCD4xDownload Raspberry Pi driver SCD4x
SEK-ControlCenter (all devices)
  • Link•
SoftwareDownload SEK-ControlCenter (all devices)Download SEK-ControlCenter (all devices)LinkDownload SEK-ControlCenter (all devices)Download SEK-ControlCenter (all devices)
Altium footprint SCD4x
  • Link•
Drawings/CADDownload Altium footprint SCD4xDownload Altium footprint SCD4xLinkDownload Altium footprint SCD4xDownload Altium footprint SCD4x
STEP file SCD4x
  • STEP•
  • 632.1 KB
Drawings/CADDownload STEP file SCD4xDownload STEP file SCD4xSTEPDownload STEP file SCD4x632.1 KBDownload STEP file SCD4x
STEP file SEK-SCD41
  • STEP•
  • 770.9 KB
Drawings/CADDownload STEP file SEK-SCD41Download STEP file SEK-SCD41STEPDownload STEP file SEK-SCD41770.9 KBDownload STEP file SEK-SCD41
Calibration certification SCD4x
  • 05/2022•
  • PDF•
  • 118.0 KB
CertificateDownload Calibration certification SCD4x05/2022Download Calibration certification SCD4xPDFDownload Calibration certification SCD4x118.0 KBDownload Calibration certification SCD4x
REACH and RoHS declaration SCDxx, STCC4 and CO2 Gadget
  • 04/2026•
  • PDF•
  • 100.9 KB
CertificateDownload REACH and RoHS declaration SCDxx, STCC4 and CO2 Gadget04/2026Download REACH and RoHS declaration SCDxx, STCC4 and CO2 GadgetPDFDownload REACH and RoHS declaration SCDxx, STCC4 and CO2 Gadget100.9 KBDownload REACH and RoHS declaration SCDxx, STCC4 and CO2 Gadget
Carbon Dioxide product flyer
  • 03/2026•
  • PDF•
  • 2.2 MB
FlyerDownload Carbon Dioxide product flyer03/2026Download Carbon Dioxide product flyerPDFDownload Carbon Dioxide product flyer2.2 MBDownload Carbon Dioxide product flyer
Carbon Dioxide product flyer Chinese
  • 03/2026•
  • PDF•
  • 1.3 MB
FlyerDownload Carbon Dioxide product flyer Chinese03/2026Download Carbon Dioxide product flyer ChinesePDFDownload Carbon Dioxide product flyer Chinese1.3 MBDownload Carbon Dioxide product flyer Chinese
What types of NDIR sensors exist and how do they work?
  • 05/2022•
  • PDF•
  • 146.5 KB
Application noteDownload What types of NDIR sensors exist and how do they work?05/2022Download What types of NDIR sensors exist and how do they work?PDFDownload What types of NDIR sensors exist and how do they work?146.5 KBDownload What types of NDIR sensors exist and how do they work?
What types of NDIR sensors exist and how do they work? (Japanese)
  • 10/2023•
  • PDF•
  • 277.2 KB
Application noteDownload What types of NDIR sensors exist and how do they work? (Japanese)10/2023Download What types of NDIR sensors exist and how do they work? (Japanese)PDFDownload What types of NDIR sensors exist and how do they work? (Japanese)277.2 KBDownload What types of NDIR sensors exist and how do they work? (Japanese)
Carbon dioxide product flyer Japanese
  • 07/2026•
  • PDF•
  • 1.4 MB
FlyerDownload Carbon dioxide product flyer Japanese07/2026Download Carbon dioxide product flyer JapanesePDFDownload Carbon dioxide product flyer Japanese1.4 MBDownload Carbon dioxide product flyer Japanese
Indoor air quality brochure
  • 11/2025•
  • PDF•
  • 7.0 MB
FlyerDownload Indoor air quality brochure11/2025Download Indoor air quality brochurePDFDownload Indoor air quality brochure7.0 MBDownload Indoor air quality brochure
  • All products
  • •CO₂ sensors
  • •SCD4x

Sensor evaluation

Buy the following products to evaluate this sensor

NameDescriptionSeriesCategory
SEK-SCD41Evaluation kit for SCD4x series CO2 sensorsSEK-SCDxxCO₂ sensors
SEK-SensorBridgeConnecting bridge with two sensor portsSEK-SensorBridge

SEK-SCD41

Evaluation kit for SCD4x series CO2 sensors

SEK-SCDxx

CO₂ sensors

SEK-SensorBridge

Connecting bridge with two sensor ports

SEK-SensorBridge

Download the respective viewer software to start measuring

Go to download center

Start testing our sensors fast and easy with the evaluation kits

How to get started

Applications for this product

Air conditioners

Highest comfort and maximum energy efficiency enabled by advanced sensors for air conditioner

Learn more

Air purifiers

Air quality monitoring with our air purifier sensor

Learn more

IAQ Monitors

Make indoor environments safer, healthier, and more comfortable with advanced sensor monitoring

Learn more

CO₂ monitoring for better sleep quality

Understanding how ventilation impacts sleep, health, and recovery

Learn more

Demand-controlled ventilators

Maximized well-being and optimum energy efficiency with our DCV sensor

Learn more

Smart speakers

Air quality sensors turn smart speakers into intelligent indoor air monitors

Learn more

Mechanical ventilators

Precise and safe patient ventilation using ventilator flow sensors

Learn more
I²C
Size (LxWxH)10.1 x 10.1 x 6.5mm10.1 x 10.1 x 6.5mm
Packaging size60 and 600pcs (T&R)60 and 600pcs (T&R)
Temperature
Typ. temperature accuracy0.8°C0.8°C
Response time (τ63%)120s120s

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EMEA (Europe)

Part numberQuantityDistributor nameCountry
SCD40-D-R2864SOS electronicSKBuy
SCD40-D-R2600RutronikDEBuy
SCD40-D-R20Farnell UKGBBuy

The Americas

Part numberQuantityDistributor nameCountry
SCD40-D-R23501DigiKeyGlobalBuy
SCD40-D-R21800Future Electronics NAGlobalBuy
SCD40-D-R21610Mouser ElectronicsUSBuy
SCD40-D-R2600Future Electronics NAGlobalBuy
SCD40-D-R20NewarkUSBuy
SCD40-D-R20NewarkUSBuy
SCD40-D-R20Braemac AmericasUSBuy
SCD40-D-R10Mouser ElectronicsUSBuy
SCD40-D-R20Arrow ElectronicsUSBuy
SCD40-D-R20Arrow ElectronicsUSBuy