Concerning the test results in SLAA930 Application Report

Zt Liu

Prodigy 140 points

Other Parts Discussed in Thread: MSP430FR2355

Hi, there!

We're very interested in TI's dual ray/wave technique used in smoke detector development.

Now, we are evaluating MSP430FR2355, for we've read the excellent application report SLAA930.

The test result section on p.14 section 5.1 really got our attention!

We'd like to know further about the test result:

What part is the photo-diode?!

I suppose the photo-diode need to have a sensitivity range down to, say 500nm?

Also, I've noticed that in TPS8804EVM, blue led and photo-diode listed in BOM are SFH123 and LTL1CHTBK4.

The latter blue led has 470nm wavelength, however the photo-diode has spectrum from 700nm to 1100nm.

It seems that he photo-diode simply can't receive any scattered blue light, right?

Thanks for reading this post.

Zt.

over 5 years ago

0 Srinivas Lingam over 5 years ago

TI__Expert 7365 points

Hi Zt,

I will check internally and get back to you on the exact photo-diode used in SLAA930.

Srinivas

0 Zt Liu over 5 years ago in reply to Srinivas Lingam

Prodigy 140 points

Thank you, Srinivas!

I will be waiting for you further reply!

Zt.

0 Lixin Chen1 over 5 years ago in reply to Zt Liu

TI__Expert 7015 points

Hi, Zt.,

Thanks to have interest in the application report SLAA930.

The test result in 5.1 of application report SLAA930 was achieved by another dual-ray smoke detection demo board with MSP430FR2355 instead of board TPS8804EVM, So the IR LED, Blue LED and photodiode are different from the components in TPS8804EVM,

This demo board with MSP430FR2355 is single chip solution for dual-ray smoke detection. The concept block diagram is like the Figure 4 in SLAA930.

Yes, you are correct. The photodiode sensitive wavelenth needs to cover both the range of selected IR LED emitting wavelength and Blue emitting wavelength. This is implemented for the dual-ray smoke detection demo board.

Thanks,

Lixin

0 Lixin Chen1 over 5 years ago in reply to Lixin Chen1

TI__Expert 7015 points

Hi, Zt.,

If my comments answered your question, could you help to click on "this resolved my issue" button?

Thanks,

Lixin

0 Zt Liu over 5 years ago in reply to Lixin Chen1

Prodigy 140 points

Lixin,

Even though I still don't know the part number of the photo-diode in question,

I still marked it resolved anyway.

Because your fast response and kindly support. :)

Zt.

0 cb1_mobile over 5 years ago in reply to Zt Liu

Guru 117855 points

Greetings,

Really ... what was resolved? Our tech firm also noted the photo-diode in question remained HIDDEN!

(does not our posting equally deserve a, "This Resolved" - as it highlights the incomplete response?)

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Concerning the test results in SLAA930 Application Report