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> With this architecture, the sensor achieves a high level of precision, offering an accuracy of ±50 ppm ±5% between 400 ppm and 3,000 ppm. The overall range of the sensor is from 0 to 32,000 ppm.

What does the back to back ± mean? Is that the variance of accuracy from device to device? Or does the 5% reference the specific range of 400-3000?

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It's saying that it could be either +/-50 ppm from the actual reading, or +/-5% from the actual reading, whichever is worse.

> It's saying that it could be either +/-50 ppm from the actual reading, or +/-5% from the actual reading, whichever is worse.

No, it's stacked, and strictly applicable between 400-3000 ppm as characterized (despite 0-32000 ppm operating range by design).

At the lower 400 ppm end, accuracy is +/- 50 ppm +/- 20 ppm = +/- 70 ppm.

At the upper 3000 ppm end, accuracy is +/- 50 ppm +/- 150 ppm = +/- 170 ppm.

Also worth noting that the calibrated reference used to determine this published accuracy has an uncertainty of +/- 2%; ref datahseet[1] Table 7.

Caveat emptor: this published accuracy can't be trusted at face value when sampling more than 1 meas/min; ref ibid.[1] Table 4.

[1] https://www.infineon.com/dgdl/Infineon-PASCO2V15-DataSheet-v...

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