X Lamp3 7090 confusion

[OldNick]

The data sheet for these indicates 76 Lm at 700mA. Given a max FV of 4.5 volts I am assuming that the FV would be about 4.2 V.

That makes them put out about 25Lm/watt.

I am at a bit of a loss. What gives?

Any help appreciated.

Nick

 

[ejot]

What is the confusion exactly? It's been 5 years since these were introduced, and great strides have been made in luminous efficacy since.

Do you know what bin you have? These were available up to 116lm @ 700mA (R bin). Perhaps the typical Vf's are lower than you're assuming too? Do you have a way to test Vf's?

 

[OldNick]

I don't actually have any. I was looking to buy a few single-die high power LEDs.

The confusion is that Cutter's are selling them for about $10 each.
http://www.cutter.com.au/proddetail.php?prod=cut195
I figured this was something new, but the data sheet link on their site is what showed the low output.

These are called XLamp 3, and I thought the old ones were just XLamp.