Sensirion SCD43
High-accuracy photoacoustic NDIR CO₂ sensor for demanding building monitoring applications.
Key Specifications
How Photoacoustic CO₂ Sensing Works
The sensor modulates infrared light near a CO₂ absorption wavelength. When the gas absorbs the light, periodic heating creates a small pressure or acoustic signal. An acoustic detector measures the signal and the device’s electronics estimate carbon dioxide concentration, applying compensation and calibration as specified by the manufacturer.
Integration Considerations
Verify measurement conditions, automatic baseline correction requirements, installation environment, power peaks, bus communications, humidity and pressure effects, and manufacturer lifecycle status before product selection. Accuracy ranges should not be confused with digital reporting or output ranges.
Official Manufacturer Source
Product information and lifecycle status should be checked against the current manufacturer listing.
View SCD43 official product page →AirAlign is an independent technical information resource and is not affiliated with Sensirion. Specifications and product availability can change.
SCD43 — highest published SCD4x accuracy grade — model-specific datasheet review
These original manufacturer specifications are bounded to their stated measurement conditions. Output coding, calibrated precision, voltage domains, firmware and lifecycle status are not universal across variants.
| Property | Official model specification | Engineering limitation |
|---|---|---|
| Physical principle | SCD4x photoacoustic NDIR with SHT4x RH/T compensation | Same broad sensing architecture as SCD40/41, different rated accuracy. |
| Specified CO₂ range | 400–5,000 ppm | Digital 0–40,000 ppm output range is not the calibrated accuracy range. |
| CO₂ accuracy | ±(30 ppm + 3% of measured value) | At 1,000 ppm, combined listed limit is approximately ±60 ppm in stated conditions. |
| Response | CO₂ τ63 ~60 seconds | Slow chamber response affects control-loop transient timing. |
| Supply and current | 2.4–5.5 V; ~15 mA average and 205 mA peak (maker settings) | Do not budget low-power IoT regulator for 15 mA alone. |
| Electrical/mechanical | I²C, 10.1 × 10.1 × 6.5 mm SMD | Check embedded firmware support and handling/reflow guidelines. |
| RH/T channels | Typical RH ~±6%RH and temperature ±0.8 °C | Integrated RH/T are principally compensated ancillary values, not high-accuracy lab references. |
Selection, calibration and application
SCD43 is marketed toward stricter building-monitoring targets and has the best published SCD4x accuracy in the cited CO₂ band. The OEM references compatibility with RESET grade B, WELL and other standards; that does not individually certify a fully assembled AirAlign-listed enclosure or completed building installation. Verify ambient pressure correction, temperature offset, fresh-air ASC assumptions and reference accuracy before using CO₂ thresholds for DCV. Ensure the selected SKU is in active production and the device has the SCD43-specific command/firmware support.
Original manufacturer references: SCD43 — highest published SCD4x accuracy grade official product data. Latest order code, precise calibrated concentration band and regulatory requirements must be checked before deploying a sensing or safety solution.
AirAlign technical editorial review, 25 October 2026. Not a substitute for current device-specific measurement calibration or certificates.