Samsung Sunnix5 and slug connection - confused

[Stromberg]

I've previously used power leds that are attached to PCB's, so electrical isolation of the led slug has not been an issue. Now I'm intrested of these Samsung "Sunnix5" 3 watt emitters without PCB:

http://www.led1.de/shop/product_inf...n-slhnnwh531t0-p-1076&cName=samsung-led-c-227

If I have got it right, when using bare emitters, slugs should be electrically isolated from the actual heatsink, especially when multiple emitters are used, correct?

But then I happened to read this Samsung manual about Sunnix:

http://samsung.led1.de/images/stories/file/datasheets/sunnix5/SLHNNWH531TO.pdf

..and there was a remark that: "Make sure the heatsink is electrically connected to the anode". Is this an error or have I just misunderstood something..?:thinking:

For example let's say that I'm using several of those Sunnix5 emitters connected in serial circuit and they are using the same heatsink. How should I do the slug/heatsink connection/isolation?

 

[Oznog]

They could be on one big heatsink spreader in a parallel common-anode config with individual cathode ballast resistors, then the spreader is isolated from the sink.

It is somewhat unusual to REQUIRE the sink be connected to a pin. Luxeons for example said the slug is "not electrically neutral" yet NOT common with either pin. Some devices DO have a slug which is electrically common to anode (or cathode), but it's unusual that your spec seems to require it. Maybe this was bad wording on the spec's part? I don't know how you'd expect people to tie the anode to an aluminum heatsink. And "heat sink is to be soldered, if not use heat conductive adhesive". Well, thermal adhesive does not give a consistent electrical connection, so it's not gonna be possible to guarantee slug is electrically connected to anode.

I'm inclined to suspect the spec misworded that.

 

[Stromberg]

Thanks for your reply. Pity those product specs are so weird in this matter because that Sunnix emitter seems somewhat easier to solder than many other emitters.