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Sensirion CO2 Sensor SCD4x

Next generation sensor offering unmatched price-to-performance

The SCD4x is Sensirion’s next generation miniature CO2 sensor that offers an unmatched price-to-performance ratio.

This sensor builds on the photoacoustic sensing principle and Sensirion’s patented PASens® and CMOSens® technology to enable unmatched small sensor size combined with high performance. SMD compatibility and the small footprint allow cost- and space-effective integration of boost freedom of design for customers. The integrated best-in class humidity and temperature sensor enables superior on-chip signal compensation and addition RH and T outputs. Finally, the large supply voltage (2.4 V – 5.5 V), the robustness towards external stresses and the adjustable power consumption make the SCD4x the perfect fit for varying customer needs.

Tape and reel packaging combined with its SMD assembly processing make the SCD4x ideal for high-volume applications.

SCD4x Key Features

  • Size: 10.1 x 10.1 x 6.5 mm3
  • Mounting type: SMD
  • Interface: I²C
  • Supply voltage range: 2.4 to 5.5 V
  • Current consumption:
    • 17 mA (meas. rate = 5 s)
    • 0.5 mA (meas. rate = 5 min)
  • On-chip RH and T compensation: yes
  • Output range: 0 to 40,000 ppm


  • Demand-controlled ventilation
  • Indoor air quality monitoring
  • CO2 ventilation alarm
  • IoT / Smart Home
  • Agriculture / Green housing
  • Industrial


PASens® Technology

PASens® Technology is based on the photoacoustic sensing principle which allows extreme miniaturization of the CO2 sensor without compromising sensor performance. This is because the sensor sensitivity is independent of the optical cavity size. The reduced size and the smaller number of integrated components result in a highly price-efficient BOM structure. Thanks to the miniaturizing and the economical BOM structure of these new CO2 sensor, the SCD4x will open up numerous possibilities for a whole new set of products and applications.


SCD4x Functional Block Diagram

Sensirion — SCD4x Functional Block Diagram