Interesting 5mm white LED

This may be olde news. I was goofing-off at work reading Digikey's latest catalog and stumbled on Lumex's "patent-pending" new DSP extremely low Vf LEDs. I went nyuknyuk- so that's whose making the suckers! (MJ LED /ubbthreads/images/graemlins/grin.gif ) I ordered 10 for the price break. They're here. They arrived today, and looked kinda funny!

There's a surface mount component on the dome side and the back of the die area has a white epoxy blob to cover some whatever-they-call-it circuitry. I don't see an inductor, so probably a charge pump of some kind. I popped the CR2 out of my pocket light and tried one. Bluish-white and, unlike the MJLED, not particularly impressive. /ubbthreads/images/graemlins/frown.gif

(Mike and Lambda /ubbthreads/images/graemlins/crackup.gif I hope. /ubbthreads/images/graemlins/grin.gif )

Larry

looks like they might be fun to play with

PM me with your addy- I aint impressed X10! /ubbthreads/images/graemlins/grin.gif

Larry

I'm surprised it's taken so long for a product like this to make it to market. I guess it's too much to hope for that the in-package boost circuit is current-limiting.

Cool. I wonder if Craig has seen these yet. So they aren't bright or are they super blue? What's the vF to run at specs?

If they are decent bright I might take one off your hands for a mag solitare... /ubbthreads/images/graemlins/smile.gif

It appears from the datasheet/website that they are only pushing 2.5mA through the die on the White, Blue, Green? Humm, 1900mcd.

http://www.lumex.com/product.asp?id=1006106

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IsaacHayes said:
Cool. I wonder if Craig has seen these yet.

[/ QUOTE ]
This thread is the first time I've heard about these LEDs.
If Larry wants to send me one, I'll test it however necessary to determine its basic specifications: intensity, Vf, & If.

Neat part.

I suspect it's about as bright as it can be, the 5 mm package is very bad getting rid of heat. It was never intended for this, right? Designed for 20 mA 2 volt parts at first. Since very little power comes out as light, we have to worry about every mW in.

Not to mention it's hard to build a bity converter. You need a reactive element of some sort (inductor or capacitor) both of which have serious physical constraints on size.

Doug Owen

what happens if you power them with 3v? /ubbthreads/images/graemlins/grin.gif


Pablo

If these are the same parts MJ uses, they work fine at 3v. The spec says 3.2v is ok. I'm interested in seeing Craig's measurements if Larry sends Craig one of the leds. It might be a nice way to set up a 1x2032 coin cell light, for example.

It's not the same as the MJLED. There are no external die components(capacitor) on the MJLED. The spec sheet on the Lumex says max 3.2 volts.

I powered one with 3V and it was not as annoying to look directly into as an Arc AAA from 1 foot. They're definately not the basis for the MJLED nor are they as bright.

Larry

Yeah, I had the impression before that the MJ led is an ISP Korea 100 mA led selected for a low voltage bin, so at 3 volts it's still getting reasonable brightness.

Hi Paul,

You want a couple? (Just addressed envalopes for Craig and Mark.)

Larry

kool what do I owe you

how low can you go on the voltage and still get decent light from them ?

Larry, hmm, I think in reality I wouldn't do anything interesting with them except make some measurements, and Craig's going to do a better job of that. If you don't have other takers I guess I still wouldn't mind playing with one. Thanks!

Markdi,

Freebie and the envalope's addressed. Same for Craig and Newbie. Again, I'm not impressed with the one I tried, and have zero plans for them! 2nd prize is two of 'em, and we have 3 winners tied! /ubbthreads/images/graemlins/grin.gif

Larry

thank you very much

Mark Dikeman

How bright are these things at 1.5v?
Might make a quick and cheap LED ugprade for a solitare!