3w in a 5mm?

[snakebite]

1.0W 5mm LED Diodes

Has efficiency improved this much that this is possible?

 

[idleprocess]

All ratings are using what looks like a trick of 20 years ago - 25°C ambient, unspecified junction temperature (very likely a similar work of fiction - 35°C). Appears to have ... nominal ... provision for heatsinking the reflector cup lead. ~75 lm/W at 700mA, assuming the temp derate doesn't catch up to you within milliseconds.

It's not impossible that it might hit spec for the first couple of seconds in a cold environment. Whether or not it lasts very long being hammered like that is another matter.

 

[LEDphile]

I note that the Tj to Ts thermal resistance isn't specified, so it isn't even possible to calculate the actual junction temperature. And 60 lm/W for a 6000K LED (at low CRI, based on the spectral graph) is frankly embarrassing these days, even with an optic - that's on par with a Cree XR-E or XP-E with an R2 flux bin.

 

[idleprocess]

I note that the Tj to Ts thermal resistance isn't specified, so it isn't even possible to calculate the actual junction temperature.

Yeah that struck me too. Here's the datasheet for the "3W" part.

 

[Dave_H]

The title says 1W, the spec says 3W, unlikely continuous in a package such as this. Datasheet note states pulsed power at 10% duty cycle. These are "Absolute Maximum" ratings which are not for continuous use.

Dave

 

[idleprocess]

The title says 1W, the spec says 3W, unlikely continuous in a package such as this. Datasheet note states pulsed power at 10% duty cycle. These are "Absolute Maximum" ratings which are not for continuous use.

Spec sheet is calling out 150-180lm @ 700mA or ~2W. Still a lot of power for what's nominally been a <100mW package.

The 1000mA has an interesting caveat:

1) Max. pulse conditions of 1/10 duty, 0.1msec max. pulse width

10% duty cycle at 100µs. To me this suggests a special application in mind such as a strobe unit, perhaps for machine vision applications.

... which also drew me to the second footnote:

2) It is recommended that the temperature of Lead Frame not be higher than 90 ºC.

@LEDphile
Seems this is the closest it gets to calling out thermal resistance - +35°C vs ambient, best case.

 

[Dave_H]

Sort of wondering what the application for this would be. Leaded LEDs at higher power (unless it's pulsed low duty-cycle) doesn't make a lot of sense.

Some will recall very early LED ac bulbs using leaded 5mm or similar LEDs, known as "showerheads"; most didn't hold up well (LOA...LOL). They were low-power LEDs typically 100mW class.

Dave

 

[HarryN]

Some LEDs are used as the "flash" of cell phones and similar.

Here is an example from Lumileds. They were early in that market - no idea about now.

LUXEON Flash

Lumileds technical innovations have produced the world’s first color tunable product, high CRI flash LED, and mid-power camera flash LED.

lumileds.com

 

[bshanahan14rulz]

Some will recall very early LED ac bulbs using leaded 5mm or similar LEDs, known as "showerheads"; most didn't hold up well (LOA...LOL). They were low-power LEDs typically 100mW class.

Ah yeah, I remember buying a baggie of ebay "5-chip LED" style 5mm LEDs. Nice color, very good brightness, starts dimming after a few seconds just from heat, get way hotter than a 5mm package should. Spent unexpected time dealing with power management after realizing that the "specs" on the package were not sustainable.

LOA damaged LED reputation so badly in the early days, IMO.

 

[alpg88]

Meh, I used those, 5 and 10mm, their legs get extremely hot at 100ma, even thou negative leg has a heatsink. But they do look good at half the current when each chip is visible. As a decoration lights they are great, but to illuminate, not so much.

 

[bshanahan14rulz]

Hah, randomly found some old photos, here's a pic of the LEDs I used. Yeah, you can kinda see the "heatsink" bit

From an old schematic I drew, it looks like I drove these at 80mA, PWM'd for dimming, with thick copper wire to connect the "heatsink" leads, and still had plastic-meltingly hot.