Sensirion SGP40

Metal oxide VOC sensor with digital VOC Index processing for indoor air quality.

Product Overview

Manufacturer: Sensirion
Product: SGP40
Type: OEM / integrated measurement sensor
Range / measured parameters: VOC Index; not a compound-specific TVOC concentration
Communication / outputs: I²C

Engineering and Selection Considerations

Confirm the exact manufacturer’s ordering code, current availability, calibrated measurement range, output protocol, power supply, operating environment and mounting requirements. Technical parameters can change between models, ordered options or product generations.

Official Technical Documentation

Official manufacturer product information →

Independent AirAlign product reference. Source reviewed 13 October 2026. The manufacturer’s technical documents remain authoritative.

SGP40 — VOC Index cannot be sold as ppm TVOC

The SGP40 is a metal-oxide VOC sensing element whose digital response is normally interpreted with Sensirion’s VOC Index algorithm. Its output is not an independently calibrated ppm of formaldehyde or a universal TVOC mg/m³ value. The host needs compatible I²C voltage/timing, environmental humidity compensation from other sensors and algorithm state handling after power cycles. High solvent exposure or enclosure contamination can affect response and recovery, so use trend-driven ventilation controls with appropriate filtering.

SGP40 — VOC Index architecture and CMOSens MOX behavior — detailed specification and application review

Original Sensirion source verified against this exact model. Manufacturer values relate to the stated test conditions and are not transferable to every platform/suffix.

Parameter	Original manufacturer data	Design interpretation
Technology	Heated metal-oxide (MOX) VOC-sensitive die with raw 16-bit digital signal	Sensor responds to a mixture of gases; it is not a selective formaldehyde, benzene or absolute TVOC analyzer.
Processed VOC output	VOC Index algorithm 0–500	Index 100 is a relative baseline, not 100 ppm or 100 µg/m³.
Measurement / response	Manufacturer catalog gives <10 s τ63 for VOC signals under controlled conditions	Dynamic gas-index adaptation may take much longer than a raw-sensor response.
Supply voltage	1.7–3.6 V	Use I²C pullups referenced to a supported logic rail.
Average / peak current	Approximately 2.6 mA average / 3.0 mA max by manufacturer catalog	Heater duty and firmware sample schedule affect power budgets.
I²C and package	I²C; 2.44 × 2.44 × 0.85 mm DFN footprint	SMD integration needs appropriate exposure to ambient air and ESD handling.
On-chip compensation	Humidity compensation, with external RH/T inputs to algorithms	Absolute humidity input and continuous algorithm state improve trend comparability.

Integration, calibration and data-quality guidance

Sensirion’s SGP40 primarily supplies raw air-quality information; the VOC Index algorithm must be run/maintained according to Sensirion’s current guidance. Do not label its processed 0–500 index as a chemically calibrated concentration or use it for a worker exposure alarm. Initialize and persist baseline across normal operation where the driver supports it, and handle gas-index stabilization after power loss. Check the maker’s app guidance for solvent, cleaning-agent and humidity disturbances, and never claim NOx detection: that is an additional SGP41 channel, not a hidden SGP40 software option.

Primary source: Sensirion SGP40 official product specifications and downloadable technical documents. Final firmware, ordered variant and certificate checks remain part of commissioning.

AirAlign technical editorial update · 25 October 2026. OEM claims paraphrased for engineering selection, not independent calibration signoff.