OPT3001-Q1: Measurement output variation

Hi Youhei,

Can you explain what you mean by "initial tolerance" in the first question?

If you are referring to variation due to noise, the maximum variation at full scale 40.95Lux will not exceed 0.12 lux.

Thank you,

Brent Elliott

Hi Youhei,

The 1800 to 2200 lux limits is guaranteed for units in production.

Thank you,

Brent Elliott

Hi Youhei,

If the device is calibrated perfectly, then if 38 lux is shined on the device, the device min will be 37.88 and max 38.12 based on the 0.12 lux variation. However in practice there may be some added error from the 2% linearity spec, temperature, etc.

Thank you,

Brent Elliott

Hi Youhei,

By calibrated perfectly, I mean that the output of the device is tested with a known lux shining on the device, and a correction factor is applied so that the % error is eliminated. This is explained below in the "Light Sensor Calibration in the Lab" video:

https://www.ti.com/video/series/precision-labs/ti-precision-labs-ambient-light-sensors.html

The rest of the variation is due to factors that may effect the output which are listed in the datasheet specs, like power supply variation (varies in %/V), temperature variation (varies in %/C), linearity, accuracy between gain ranges, etc.

Depending on the use case, the variation could be higher or lower. For instance, since you most likely won't change the supply voltage, after the initial calibration, the supply voltage variation won't need to be considered. Also, the variation from temperature will increase or decrease depending on the size of the temperature range you are going to use.

I hope this helps.

Thank you,

Brent Elliott