Luxeon III Star

Upon reading the DS46 Luxeon 3 datasheet carefully I noticed a sidenote on page 2 that states "Electrical insulation between neighboring stars is required - aluminum board is not electrically neutral". When I measure between the aluminum base and the plus or minus terminal I get an infinite resistance reading. Does anyone know what Luxeon is talking about?

The base of the star is electrically isolated from the + | - of the luxeon.

I have noticed the inconsistent mention of electrical isolation.. i've used luxeon stars while still attached without incident.. my guess is that they use the likes of arctic alumina to attache them which is an electrical insulator so it's a moot point. Was the datasheet for a star or an emitter?

Given the construction of the Luxeon III, there is no guarantee that the slug of the emitter will be electrically isolated from the aluminium of the star board.

There are ESD protection diodes between the slug and each electrical lead of the emitter. Given the right electrical configuration, it's possible to forward bias one of these diodes, and possibly fuse open one of the bond wires, rendering the Luxeon dead.

Thus, it's best to follow the directions and try to ensure electrical isolation between stars.

OK, I bit the bullet and sacrificed a device. The lens and black plastic contact assembly was glued on. Removing it broke the wire bonds. The LED sits on a metal piece that is glued to the aluminum star base. This "glue" apparently is thermally conductive and electrically non-conductive. So it appears that if they get a good 100% glue layer between the LED pedestal and the star base you are isolated. Apparently they don't guarentee this. I guess if you are going to hook several in series you should check for isolation of eash device or insulate. Comments? Thanks for the replys. Mick

By no means should you have to have had to sacrifice a emmiter, Mick. Just desolder the leads and bend the star.

But yes you are right, there is generally good insulation between the stars.

Jay