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OPT3004: lux reading issue

Roger Lin
Expert 3350 points
Part Number: OPT3004

Tool/software:

Hi team,

My customer are currently experiencing an issue during product testing involving the OPT3004 Ambient Light Sensor.

 

In our analysis, one sensor returned a lux reading of 1719 lux under an applied illumination of approximately 2298 lux.

Based on this result, our internal engineer concluded that the sensor is NG, since it falls outside the expected output range under such lighting.

 

However, according to the OPT3004 datasheet, the Electrical Characteristics table specifies accuracy only under the condition of 2000 lux white LED illumination,

where the acceptable output range is 1600–2400 lux

 

We would like to confirm with TI:

  1. Is it valid to apply a 2298 lux input and expect a proportionally scaled lux output using interpolation?
  2. Does TI define an official accuracy range or test methodology for lux inputs outside the 2000 lux condition (e.g., 2298 lux)?
  3. If the sensor reads 1719 lux at 2298 lux input, is that considered out-of-spec?

Thanks

  • 0
    TI__Expert 4460 points

    Hello Roger, 

    How is lux reference being determined and what is the light source?

    Thank you, 

    Josph Scherphorn

  • 0 in reply to Joseph Scherphorn
    Prodigy 60 points

    Hi Joseph, the model OPT3004 Ambient Light Sensor (ALS) With Excellent Angular IR Rejection ( SOT-5X3 package) 

    1. Lux reference was measured using a calibrated lux meter placed next to the sensor during the test.

    2. The light source used was a standard white LED, with the light intensity adjusted to reach approximately 2298 lux at the sensor surface

  • 0 in reply to Zoe Hoang
    Prodigy 60 points

    + adding information

     Hi Joseph Scherphorn  

    Firstly, I need to provide more information for you

    Background:

    During functional testing, our team observed that some sensors returned a lux output significantly lower than expected. Specifically, one sensor returned 1719 lux under a controlled white LED light source with a measured illumination of 2298 lux (measured using a calibrated lux meter – [insert device model if available]).

    Our internal PE engineer evaluated this result by proportionally scaling the accuracy range defined in the datasheet at 2000 lux (acceptable range: 1600–2400 lux). Based on this, they calculated that at 2298 lux, the expected output should fall within 1838.4–2757.6 lux.

    Since the actual sensor reading was 1719 lux, it was determined as NG due to falling below the scaled expected output range.

    ❖ Our questions

    1. Is it valid to apply a 2298 lux input and interpolate the acceptable output range from the 2000 lux baseline specified in the datasheet?

    2. Does TI officially define an accuracy range or test method for lux input values other than 2000 lux (e.g .for 2298 lux)?

    3. Based on the measured 2298 lux input (under white LED), is a returned value of 1719 lux considered out-of-spec?

    4. Does the "0.01 lux to 83k lux" measurement range mentioned in the datasheet imply the sensor maintains accuracy across this full range, or is accuracy guaranteed only at 2000 lux?

    Additionally, TI asked:

    “How is lux reference being determined and what is the light source?”

    We confirm:

    • The lux reference was obtained using a calibrated lux meter 

      a calibrated lux metera calibrated lux meter

    • The light source is a white LED, consistent with the datasheet condition.

    We would greatly appreciate your guidance on whether the interpolation approach our engineer used is acceptable and whether such a 1719-lux reading under 2298-lux illumination is officially out-of-spec.

    Looking forward to your response.

  • 0 in reply to Zoe Hoang
    TI__Expert 4460 points

    Hello Zoe, 

    I want to get some more information on the parts you have. Could you please provide a picture of the label with the lot trace code. This will help us in supporting your concern. 

    Thank you, 

    Joseph Scherphorn

  • 0 in reply to Joseph Scherphorn
    Prodigy 60 points

    Hi Joseph

    SMT=> PCBA Test=> ASSY : and the issue happened in ALS TEST STATION. Therefore, no long the label to know exactly which roll of material and which label is defective. So is there any other way to check? and as my main question is

    1. Is it valid to apply a 2298 lux input and interpolate the acceptable output range from the 2000 lux baseline specified in the datasheet?

    2. Does TI officially define an accuracy range or test method for lux input values other than 2000 lux (e.g .for 2298 lux)?

    3. Based on the measured 2298 lux input (under white LED), is a returned value of 1719 lux considered out-of-spec?

    4. Does the "0.01 lux to 83k lux" measurement range mentioned in the datasheet imply the sensor maintains accuracy across this full range, or is accuracy guaranteed only at 2000 lux?

    Additonally, if you need the picture label from other rolls, I can provide for you.

  • 0 in reply to Zoe Hoang
    TI__Expert 4460 points

    Hello Zoe, 

    This is not expected but I'd need to verify the testing setup before commenting further.

    Could you provide image of test setup. And test documentation/procedure?

    Has low lux reporting behavior been isolated to this device? (Such as through AB swap)

    How many devices have been tested so far? 

    Thank you, 

    Joseph Scherphorn

  • 0 in reply to Joseph Scherphorn
    Prodigy 60 points

    Hi Joseph

    please help me to check the report describing the error phenomenon file:///C:/Users/83000670/Downloads/Parrot_Light-sensor-issue.html

    The sensor is tested at the ALS test station during the PCBA functional process.

  • 0 in reply to Joseph Scherphorn
    Prodigy 60 points

    Hi Joseph Scherphorn, Hope you can understand my question. I evaluate the results based on the specification.

  • 0 in reply to Zoe Hoang
    TI__Expert 4460 points

    Hello Zoe, 

    This is one single unit correct? Out of how many tested?

    Testing protocols seem reasonable. 

    I most want to understand how the reference is established and that is not clear in the images. Where is reference sensor positioned relative to OPT3004?  

    Was there supposed to be more info in file link?  I was not able to access. 

    While TI does not specifically define accuracy specification outside of 2000 lux it is valid to interpolate the acceptable output range from the stated 2000 lux specification.  

    Thank you, 

    Joseph Scherphorn