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ADPD1080 How to calculate Intensity value ?

Thread Summary

The user is trying to convert ADC values from the ADPD1080 to light intensity for a water turbidity measurement system. The final answer explains how to compute photocurrent from ADC codes using the TIA ADC mode and a 25k feedback resistor, with a resolution of 2.92nA/LSB. The user was directed to post their question in the Circuits from the Lab forum for further support.
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Hi all,

I'm trying to read ADPD1080 driver, I can got all of FIFO and the data
registers. But, I down know how to convert the value into Intensity. My goad is Water Turbidity Measurement System

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  • Hi Lee,

    By intensity are you referring to the light sampled by the photodetectors? The ADPD1080 measures the current signal (photocurrent) from the photodiode. Photodiodes generally have different wavelength characteristics but you should be able to get the illuminance (usually measured in lux or lx) from the photocurrent using the characteristics plot in the datasheet.

    You can compute the photocurrent from the ADC code using the settings you have for the TIA. For example in TIA ADC mode (bandpass filter and integrator are skipped in this mode), table 29 of the datasheet shows that the TIA ADC resolution using a 25k feedback resistor is 2.92nA/LSB

    Regards,

    Nikko

  •  why I config the current as the table,the ADC value gap vary much?

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