OPT3101: Select an emit led for 2m

Joe Wang(SE)

Part Number: OPT3101

Hi Alex,

After we have a meeting with customer yesterday, Customer now has two questions and I am also not clear, hope you can give some answer:

the first is whether the data from the crosstalk calibration and the temperature phase calibration needs to be imported before the ambient phase calibration, and will the first two steps have an impact on the ambient phase calibration?
The second problem is that our emitter led model is SFH 4556 with a measurement distance of 1.6m, the customer wants to reach 2m, and need the total angle of the 3 emitters is >90, Whether we need to re-select the emitter led , and if so, which led should we choose?

Could you please take your time to give me some answer or suggestions?

Thanks.

over 2 years ago

0 Alex Bhandari-Young over 2 years ago

TI__Mastermind 25815 points

Hi Joe,

1. Yes this should be done. All previous calibrations should always be loaded to ensure the current calibration does not have any residual effects from previous calibrations not being applied. You should also be loading phase temp calibration before running phase ambient.

2. What do you mean by "SFH 4556 with a measurement distance of 1.6m"? If this using the 3ch TI EVM board you are referring to? If so the EVM is 120 degrees FoV so if they could shrink the FoV to increase the range of the device. The challenge here will be to find high performance LED and PD with the proper FoV. Just changing PD may also allow them to increase range. They will need to use the system estimator tool to check this and choose components properly. If they start this process and have questions we can help to answer them.

Best,

Alex

0 Joe Wang(SE) over 2 years ago in reply to Alex Bhandari-Young

TI__Intellectual 1100 points

Hi Alex,

Thanks for your help!

Yes, they use the 3ch board, and FOV is 120 degrees. the emit led is SFH4556 with half angle of 20 degree , So the same led, if they shrink the FOV, like 90degrees, the detect range will increase? If this is ok, is more simple, they don't need change the led, but if not ok, they have to choose an new led or PD.

Thanks

Best Regard

Joe

0 Alex Bhandari-Young over 2 years ago in reply to Joe Wang(SE)

TI__Mastermind 25815 points

Hi Joe,

The 120 board uses 3x 40 degrees LEDs (+/-20 deg). If you shrink PD FoV to 90 deg then the middle channel will still have 40 degree FoV and the two side channels will only have 25 degree each. This could increase the range of the center channel given a narrower PD can capture more light from the center channel. However, I'd expect the range of the side channels to decrease because the PD will capture less light from those LEDs. Of course the optimal solution is to use 3x +/-15 deg LEDs and a +/-45 deg PD, but they would need to check if these components are available.

Best,

Alex

0 Joe Wang(SE) over 2 years ago in reply to Alex Bhandari-Young

TI__Intellectual 1100 points

Hi Alex,

OK. got it. Thanks again.

Best,

Joe

0 Joe Wang(SE) over 2 years ago in reply to Alex Bhandari-Young

TI__Intellectual 1100 points

Hi Alex,

I just found an emit led SFH 4350, Radial T1, SFH 4350 | OSRAM Opto Semiconductors, Compared to SFH4556, I think this can measure a longer distance , but can it match the OPT3101? When I select a emit, what factors should I consider with regard to the OPT3101?

0 Alex Bhandari-Young over 2 years ago in reply to Joe Wang(SE)

TI__Mastermind 25815 points

Hi Joe,

You can check here: 6.2 Emitter Specification Parameters in https://www.ti.com/lit/an/sbau305b/sbau305b.pdf

It lists the important parameters to check for LED.

Best,

Alex

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OPT3101: Select an emit led for 2m