High temperature LED - Page 1
Forum section: electronics / projects

author: kuon
author_rank: Regular Contributor
timestamp: October 14, 2022, 06:51:00 am
content: Hello,I need led indicators (red/green SMD 0805 or similar with 2-10mA current) that can operate at 120°C.I searched for a while now and I can't find anything. I played with most distributor parametric search as well as octopart's.Do you know anything? Or maybe another parametric search tool I could have missed?

author: Someone
author_rank: Super Contributor
timestamp: October 14, 2022, 07:09:20 am
content: Price?Luxeon (Rebel line ?) has some ceramic packages that will go up into that range

author: kuon
author_rank: Regular Contributor
timestamp: October 14, 2022, 07:29:06 am
content: Price is not an issue as this is not a consumer device. I looked at the rebel line, but those are high power, I have a 10mA current budget per led (5V).

author: Someone
author_rank: Super Contributor
timestamp: October 14, 2022, 07:43:25 am
content: Quote from: kuon on October 14, 2022, 07:29:06 amWhat makes you think they dont work at 10mA?Luxeon and Cree certainly have the lifetime data at the temperatures you are interested in, just avoid phosphors and it should be tickety boo. Both companies have been pretty good at providing custom bins/parts.

author: kuon
author_rank: Regular Contributor
timestamp: October 14, 2022, 07:46:28 am
content: Well, the datasheet starts at 100mA, but yeah it might light enough at 10mA, I'll have to try. Thanks

author: voltsandjolts
author_rank: Unknown
timestamp: October 14, 2022, 07:58:41 am
content: I don't know of any SM0805 LEDs that don't work at 120C, but yeh, if you want it rated for that temperature by the manufacturer then it's tricky.Longevity is another question.

author: kuon
author_rank: Regular Contributor
timestamp: October 21, 2022, 07:08:17 pm
content: I just got some Rebel from Luxeon, which are rated at 150°. They are bright enough at 10mA which is great. I tested them at full power and I am quite impressed by the brightness level they got to. Thanks.

author: jonpaul
author_rank: Super Contributor
timestamp: October 21, 2022, 07:21:42 pm
content: 120c AMBIENT or 120 C Junction temp?Jon

author: kuon
author_rank: Regular Contributor
timestamp: October 21, 2022, 07:34:31 pm
content: 120°C ambient

author: mzzj
author_rank: Super Contributor
timestamp: October 21, 2022, 07:34:57 pm
content: Quote from: jonpaul on October 21, 2022, 07:21:42 pmWon't make much difference at 2mA, especially with the suggested power leds.50K/W thermal resistance from junction to ambient and <0,02W power loss makes 1 degree difference between junction and ambient temp.

author: Zero999
author_rank: Super Contributor
timestamp: October 22, 2022, 08:22:12 am
content: Just one question: why? If it's inside an oven, or heater, then go for incandescent. The extra power isn't wasted, but goes into heating the oven.

author: magic
author_rank: Super Contributor
timestamp: October 22, 2022, 09:44:22 am
content: Where are you getting incandescents in 0805 package?

author: Zero999
author_rank: Super Contributor
timestamp: October 22, 2022, 10:02:28 am
content: Quote from: magic on October 22, 2022, 09:44:22 amWell there are very small wheat grain sized incandescent lamps, but fair point, not 0805 and they might not be bright enough. They still might be an option though.

author: kuon
author_rank: Regular Contributor
timestamp: November 10, 2022, 04:14:01 pm
content: I went for the Luxeon ones and it works very well with lower current.

author: tooki
author_rank: Super Contributor
timestamp: November 10, 2022, 08:26:05 pm
content: Quote from: Zero999 on October 22, 2022, 08:22:12 amRight? I’ve started seeing ovens with LED lighting, which just seems insane to me.

author: kuon
author_rank: Regular Contributor
timestamp: November 10, 2022, 08:31:29 pm
content: Quote from: tooki on November 10, 2022, 08:26:05 pmIt is for visual status of sensors inside a heated chamber 3d printer. Those sensors are read from the central electronic, but I have been asked to put a direct visual feedback directly on them, for example, if the toolhead is hot, a red led will be ON next to it.

author: bidrohini
author_rank: Regular Contributor
timestamp: November 11, 2022, 07:24:04 am
content: You can take a look at digikey's high-temperature LED series:https://www.digikey.com/en/product-highlight/s/sunled/high-temperature-series-leds

author: Terry Bites
author_rank: Super Contributor
timestamp: November 14, 2022, 04:10:14 pm
content: Light pipes,fibres, mirrors etc...If you can get a wire to it you can get a fibre to it.It always helps to know what your aim really is.