The datasheets to SFH250(photodiode) and SFH757(emitter) give different values for the peak wavelengths. Emission and detection peaks are at 660 and 850 nm resp. What's the reason for that?
- posted
5 years ago
LED/DETECTOR with different peak wavelengths
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5 years ago
How about a link to the data sheets or something? GH
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5 years ago
It's not easy to tune PD sensitivity peaks, is it? The detector has 75% relative sensitivity at 660nm. OK, unless you have interferring signals at 850nm?
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Thanks,
- Win
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5 years ago
sorry a typo. it's SFH756.
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5 years ago
..Actually they both exist and are very similar...
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5 years ago
OK got it. Well you pick the LED for the wavelength you want. For the photodiodes the peak sensitivity is mostly set by the band gap of silicon and ends up near 1 um. They make 'blue enhanced' photodiodes, but they just give a bit more response in the blue.
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And the peak is still ~900 nm.
George H.
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5 years ago
Physics. Detector is Si, emitter is GaAlAs (or some alloy in the family).
Tim
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