Did Luminus update the sst-90 and sst-50 Data Sheets?

[flashfiend]

http://www.luminus.com/stuff/contentmgr/files/0/49fb13dd1ecd06ba454cc7714a96b032/miscdocs/pds_001342_rev_04_sst_90_w_product_datasheet_illumination.pdf

http://www.luminus.com/stuff/contentmgr/files/0/49fb13dd1ecd06ba454cc7714a96b032/miscdocs/pds_001342_rev_04_sst_90_w_product_datasheet_illumination.pdf

According to the Data Sheet the Luminous Flux vs. Current numbers seem higher (275% @ max rated current) and the Vf ratings look different as well. Anyone else notice this or am I high?

 

[Th232]

You're right, it does look different. Don't remember seeing the ratings at 3.15 A before.

As to whether they just chose a different point, or whether there's been an actual change I can't say since I never saved the datasheets.

 

[flashfiend]

It's just weird that if you calculate the flux vs. current curves, the max output is now 2750+ lumens.

 

[TorchBoy]

The word "preliminary" has been taken off since the last one I downloaded, and the flux is now listed @ 3.15 A instead of 350mA/mm^2. There are 4 more pages.

On page 3 the flux bins are now tested at 3.15 A instead of 3.2 A which they used to say was 350mA/mm^2, so their arithmetic is better now. Yes, the Vf figures have increased.

Ah, found the graphs you're talking about. (You could have just said what you were looking at.) Page 9 in both versions of the datasheet. That straight line doesn't look right - looks like a mistake, as it defies gravity, or at least thermal effects.

 

[flashfiend]

Sorry for not being very specific, but the raw numbers are astounding. I'm wondering if there was a change in the LEDs themselves or just new data causing revisions on the data sheets. Experiences of members around the forum seem to reflect higher Vf numbers than initially reported especially for the sst-90. This seems to be reflected more accurately in the graphs unless I'm reading them incorrectly.

 

[TorchBoy]

It truly would be astounding if there was any reason to think that Luminus had actually succeeded in not having performance (efficacy in lm/W) drop off AT ALL as current increases. The straight line means it would be just as efficient at 9 A as it is at 1 A. No one makes LEDs that can do that - it's sort of one of the holy grails of LED production. The Cree XP-G caused great excitement because it's just a few percent better at 1 amp than comparable LEDs for the same efficacy bin. Like I said, it's a mistake.

 

[flashfiend]

Your analysis of the graph makes sense. So I'm wondering if they're going to update the update?

 

[thepaan]

It looks scaled to make the line straight. Take the 100% dot at 3.15A. Times 2 would make 6.3 but the 200% line looks more like 6.5 or 6.6 to me. Also look at the last dot at 9A. It looks to me about at 275% but 275% of 3.15 is only 8.6-8.7. 250% at an even gain should have the line crossing at 7.5A when it clearly passes higher than 8.

In short: the graph looks o.k. to me.

 

[AlexLED]

Ah, interesting !

I saved their SST-50 datasheets on Feb 5th, if anybody wants them, let me know.

 

[TorchBoy]

It looks scaled to make the line straight. ... In short: the graph looks o.k. to me.

Are you saying they've used some weird sort of logarithmic scale on the Y axis? You should know that sort of graph shouldn't be straight if linear axes are used. Do you understand what I explained above?

 

[thepaan]

I agree that the graph looks straight and that it should probably be curved, however, it clearly indicates efficacy at 1A is greater than efficacy at 9A (contrary to what you seem to believe).

 

[TorchBoy]

I agree that the graph looks straight and that it should probably be curved, however, it clearly indicates efficacy at 1A is greater than efficacy at 9A (contrary to what you seem to believe).

Hm, I'll have another look... OK, yes, the efficacy does change along the line. My apologies, all. I think I'll give up and leave it to someone else to explain how efficacy changes with current.

The old datasheet didn't have any mention of the junction temperature being a condition. Could the LED really perform that well at 9 A if the Tj is just 25°C? (Momentarily, at least, before it heated up.) Would the output really be a straight line with that condition? I don't think so, and with the graph being a straight line, they're saying it now performs worse <3.15 A than it used to.

 

[MichaelW]

I remember looking at these about one month ago, the 4500K output was available with M-oderate CRI. Now 4000K is the highest with moderate CRI.

 

[Moddoo]

I have got to stir this up again.
I can't believe that so little has been spoken on this subject.

We're looking at an LED that may be putting out 2750 to 3300 lumens.

Should the SST90 still be driven to 10 Amps?

Will the output be in the neighborhood of 3000 to 3600 lumens at 10A?

4500K luminous leds are now available in the top flux bin.:twothumbs

Here is the older Flux graph for the '90.
Output is stated to be 1000 - 1200 mumens at 3.15A.

And here is the latest

 

[aurum]

hmm ... I thought the SST-90 puts out 2250lm?! Maybe I'm wrong

 

[amigafan2003]

hmm ... I thought the SST-90 puts out 2250lm?! Maybe I'm wrong

It does.


@ 9a

 

[aurum]

It does.


@ 9a

1200lm @ 3.15A *275% = 3300 lm