SFA40

SFA40 is an electrochemical formaldehyde sensor module from Sensirion measuring 10 x 13 x 2.4 mm, covering 0 to 1000 ppb with a detection limit below 20 ppb typical, accuracy of plus/minus 20 ppb or 20 percent typical, an average current of roughly 80 uA, an I2C interface (address 0x5D) and a lifetime above six years, with anti-dry technology and ethanol cross-sensitivity below 0.3 percent. That sensitivity at ppb level is the selection point: it resolves formaldehyde below the WHO and China GB/T 18883-2022 indoor limits, so air purifiers, air conditioners and indoor air-quality monitors can report and react to formaldehyde specifically instead of inferring it from a broad VOC signal. The SMD module format suits volume assembly, unlike the electrochemical cells that need manual handling and periodic replacement. Selection advice: order by the full packing code from the datasheet ordering table - the SFA40-D-R3 is the 1,000-piece reel form (Sensirion part 3.001.251) and the -D-R1 code is the 250-piece reel; this base SFA40 page covers the sensor itself, so confirm the exact order form your production volume needs in the RFQ. Parameters verified against Sensirion documentation.