Forward voltage binned LEDs?

[yassin.kraouch]

...thanks but i thought your first explanation was more accurate...i.e. the reel code only tells you that the leds on that reel are Vf binned, and could be in any one of three voltage bins.....but you have no way of knowing which voltage bin that is?

you can know the voltage bin on the reel, OSRAM for example put the voltage bin on the reel, in one reel you can find just one voltage BIN, don't worry about that

 

[treez]

Sorry i disagree, with osram you do not know what voltage bin you have , as the datasheet tells it.......

The problem for procuring several reels of LEDs from the same voltage bin is demonstrated with the “LS E63B” Power TOPLED from Osram-os.com…

“LS E63B” LED datasheet:
**broken link removed**
Quoting from page 2 of this datasheet:-

“In a similar manner for LED, where forward voltage groups are measured and binned, single forward voltage groups will be shipped on any one reel. E.g. LA E63B-CBEA-24-1 means that only 1 forward voltage group -3A, -3B, -4A or -4B will be shippable. In order to ensure availability, single forward voltage groups will not be orderable (see page 5 for explanation).”

Thats quoting from the datasheet

 

[yassin.kraouch]

Sorry i disagree, with osram you do not know what voltage bin you have , as the datasheet tells it.......

The problem for procuring several reels of LEDs from the same voltage bin is demonstrated with the “LS E63B” Power TOPLED from Osram-os.com…

“LS E63B” LED datasheet:
**broken link removed**
Quoting from page 2 of this datasheet:-

“In a similar manner for LED, where forward voltage groups are measured and binned, single forward voltage groups will be shipped on any one reel. E.g. LA E63B-CBEA-24-1 means that only 1 forward voltage group -3A, -3B, -4A or -4B will be shippable. In order to ensure availability, single forward voltage groups will not be orderable (see page 5 for explanation).”

Thats quoting from the datasheet

Yes i agree with you, single forward voltage can't be orderable, this is our case we are working with OSRAM, and it is not possible to order one forward voltage, but you order with the part number that include 4 forward voltage, and when you will receive reel, you will found that OSRAM put the forward voltage BIN on the reel.

 

[FvM]

Sorry i disagree, with osram you do not know what voltage bin you have , as the datasheet tells it.......

The datasheet tells something different. By the bin code printed on the reel, you know what you have, but you can't order a particular bin code.

 

[godfreyl]

That defies logic! I've been in electronics all my life and never heard of the term.

Google for 'define bin' and you won't find a definition...

Try search for "product binning". Plenty of results. Wikipedia even has a short article on it.

- - - Updated - - -

I don't actually understand this kind of communication desaster...

I suspect all his emails get routed straight to the spam folder. Changing his name and email address might work for a while, but bombarding manufacturers with endless simple repetitive questions isn't a winning strategy in the long term.

 

[treez]

and when you will receive reel, you will found that OSRAM put the forward voltage BIN on the reel.

By the bin code printed on the reel, you know what you have,

..sorry but this is not so.....if the particular forward voltage group was marked on the reel then you would be able to order specific Vf groups...and this cannot be done.

You definetely do not know what forward voltage group is on the reel unless you remove some LEDs and do an electrical test. The code on the reel simply tells you that the leds on the reel may be one of several vf bins.

bombarding manufacturers with endless simple repetitive questions isn't a winning strategy in the long term

...i beleive you must surely be on the side of the consumer in this case?.......it is highly unfortunate that we cannot order specific vf leds..........it is a fact that these led companies (not just osram, all of them) provide precious little by way of explanation on datasheets about such things.

Not one single led manufacturer provides that all important App Note , to be called "How to sucessfully use LEDs in parallel".

...i tell you, until the led manufacturers start advising on how to use leds in parallel, they will never sell many leds and fluorescents will ever reign supreme...................very few people in the world can design a led driver which can boost an input voltage to drive a long series string of leds......................those who can, are given bad references by led product companies, because they dont want their competitors to benefit from their services.
I have a friend who is an excellent led driver designer, and designer of SMPS, but all his previous companies tell all the recruitment consutancies that he is useless, because they dont want him falling into the hands of their competitors.

 

[FvM]

if the particular forward voltage group was marked on the reel then you would be able to order specific Vf groups

Why? There's an part code and a bin code, as the datasheet shows. Different bins have the same part code, so you can't order by bin code.

 

[godfreyl]

Here are the binning and labeling documents for the Cree LEDs mentioned in post 1:

**broken link removed**
**broken link removed**

Quote:

High-Efficiency White XLamp LEDs are additionally binned into forward voltage bins.
[snip]
LEDs are shipped on reels containing LEDs from
one bin and are always labeled with the appropriate bin code.

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Sorry i disagree, with osram you do not know what voltage bin you have , as the datasheet tells it.......

Page 14 of the OSRAM datasheet clearly shows the forward voltage code marked on the label.

 

[treez]

clearly shows the forward voltage code marked on the label.

all page 14 shows is a sample template....it says nothing about whether a certain bin code will be indicated.
Page 2 says it in plain language.......you can order a reel of leds, that reel of leds will have one vf group on it, but you will not know exactly which vf bin it will be.

 

[godfreyl]

Which part of "forward voltage" don't you understand?

 

[treez]

Which part of "forward voltage" don't you understand?

....Godfrey if it were only true......where on that label does it give a specific label for a single forward voltage group? (e.g. "3A" or "3B").....the answer is nowhere.
It gives a label for a group of forward voltages, and the leds on that reel could be from any one of those forward voltage groups.............the only thing that you can be sure of is that every led on that reel will be from the same Vf group.

I say this is bad news for people who want to source large numbers of same vf group leds for their "leds in parallel" products.

Also, does anyone know why people use matched leds, matched on vf, when they are twice the price of non matched leds?

 

[godfreyl]

where on that label does it give a specific label for a single forward voltage group? (e.g. "3A" or "3B")

See the example on page 5:

Also, does anyone know why people use matched leds, matched on vf, when they are twice the price of non matched leds?

Now we're back to square one. What makes you think they're twice as expensive?

In post 1 you tried to demonstrate that by showing datasheets of two different LED types, one twice the price of the other. However, both of those types of LED are Vf-binned, and labeled with the Vf bin code.

 

[treez]

i saw the example on page 5...but page 5 is not a label on a reel.

...both are vf binned, but the MX led is much more loosely vf binned

 

[godfreyl]

i saw the example on page 5...but page 5 is not a label on a reel.

For crying out loud, it's an example of the code that is printed on the label.

The picture on page 17 shows the layout of the label. On the actual label, "X-X-X" is replaced with the group code as explained on page 5, in the same way that "product code" is replaced with the actual product code, "Date code" is replaced with the actual date code etc.

 

[D.A.(Tony)Stewart]

I have always had the option to purchase LEDs binned by Voltage, Wavelength or XY coordinates and Intensity, since I deal with factory direct. Distributors on the other hand do not like to keep excess stock so are unwilling to hand pick small batches. Many offer kits like Cree, where there may be a min. order qty, MOQ.

These are my collective observations from shipping more than a million components.

- No bin criteria is always the cheapest ( not lowest voltage)
- Single bin for each parameter is unfeasible but possible, unless you end paying for the lot minus those they can immediately sell to other clients..
- Wafer production on LED chip voltage is surprisingly constant within 1% but highly variable between wafers.
- Lower Voltage are preferred where customer's driver needs it and are also more efficient and have the lowest ESR possible.
- A part with a wide tolerance on Vf IMHO indicates a wide process control on Wafer production
- Vf variance for a given chemistry or colour is only due to bulk resistance or ESR variance only @ rated current
- Every Mfg has their own bin ranges.

If you can't find a distributor who can supply answers to bin costs then I'll show you a client with insufficient demand.

Here is an example of one of my recent shipments of 5mm White LEDs. The requirements on these were a minimum MCD level and tighter XY color range. The range B11 for example is perhaps difficult to tell the difference from the next adjacent bin above it, B20 to the untrained eye and the 1st group has 200 pc.

25000-27000MCD 3.0-3.2V
B11: 200
B20: 1100

27000-29000MCD 3.0-3.2V
B10: 500
B11: 2000
B20: 6700
B21: 2000

29000-31000MCD 3.0-3.2V
B10: 1600
B11: 2500
B20: 6200
B21: 2200

total 25000 parts

=====
Note all above parts are 3.0-3.2V is due to my factory buy the best wafers for highest Iv, for which I pay much more. My experience is the tighter voltage range is a side effect, of good process control on the wafers with the highest quality for efficacy.

 

[treez]

Godfrey, my post #22 tells that you won't be able to know from the reel code which vf bin is on that reel.

No bin criteria is always the cheapest ( not lowest voltage)

......Thanks, could you provide any indication of how much cheaper "no bin criteria" can be?

If you can't find a distributor who can supply answers to bin costs then I'll show you a client with insufficient demand.

..........What would the MOQ have to be in order for a distributor to give bin costs?


In order to receive binned LEDs, does a company have to be an official "solutions provider"?....for example, "Forge Europa", is an official "Cree Solutions Provider", and they make LED PCBs comprising LEDs put in parallel on simple FR4 PCB....as follows...
**broken link removed**

....I have asked them which LEDs they are using and whether or not they are binned and whether they use 3oz copper PCB coating for improved LED thermal coupling, but they havent replied as yet.

The mentioned LED PCB does have a MOQ of 100 pieces, so presumably, with 33 LEDs per PCB, the MOQ is 3300. Whether this MOQ figure always applies, to all binned led requests, is unknown.

 

[godfreyl]

Godfrey, my post #22 tells that you won't be able to know from the reel code which vf bin is on that reel.

What you quoted in post 22 refers to the order code, not the label.

The order code does not specify a Vf bin.
The reel label does specify a Vf bin.

Page 5 clearly states:

Group Name on Label
Example: DA-4-3A

 

[treez]

The reel label does specify a Vf bin.

....right, now i see what you are talking about..................we have ourselves a datasheet which disagrees with itself...............as you clearly point out, according to page 5 the label code gives the precise Vf group...........but, page 2 (bottom) states clearly that individual vf groups cannot be ordered.

If the Vf code genuinely appeared on the reel label, then clearly, that vf group would indeed be orderable.

We are debating something and both of us are right....but we are at odds with each other.

Surely you see that if the vf group really did appear on the label then that vf group would be orderable.

i quote again here from page 2.....

In a similar manner for LED, where forward voltage groups are measured and binned, single forward voltage groups will be shipped on any one reel. E.g. LA E63B-CBEA-24-1 means that only 1 forward voltage group -3A, -3B, -4A or -4B will be shippable. In order to ensure availability, single forward voltage groups will not be orderable (see page 5 for explanation).”

"Single forward voltage groups will not be orderable" can only mean that the vf group does not appear on the label, otherwise it would be orderable.

Surely you agree that if the vf group really did appear on the label, then it would be absurd if individual vf groups could not be ordered?......i mean, just imagine going to buy a bar of chocolate in a supermarket, and you want a mars bar, so you order it and you get either a mars, a milky way, or a snickers.......and you end up with a snickers, when you wanted a mars bar....then you complain about it, and they say tough luck , we knew you wanted a mars bar, but we gave you something else, even though the mars bars are clearly marked "Mars".

 

[godfreyl]

as you clearly point out, according to page 5 the label code gives the precise Vf group...........but, page 2 (bottom) states clearly that individual vf groups cannot be ordered.

Yes, I just take that at face value, assuming they mean what they say.

If the Vf code genuinely appeared on the reel label, then clearly, that vf group would indeed be orderable.

Ideally yes, but they don't seem to work that way. Perhaps they're concerned that if they allowed everybody to order specific bin codes, then they'd keep running out of stock of the more popular ones, while sitting with a warehouse full of the less popular ones nobody asks for.

In any event, judging from some previous posts, it is possible but not easy - somewhere between "special" orders, sweet-talking the distributors, or just waving money under their nose to get their attention.

To grossly paraphrase what SunnySkyGuy wrote: Money makes people say "yes".:grin:

 

[treez]

I see, i guess you're right that the specific vf group code does appear on the label.
I think we have both highlighted how absurd the LED manufacturing industry really is.
Why dont they keep just knocking the down the price of the less popular bins until they start getting taken up i wonder?

I think you can see my point, say you go into a restaurant and order a "meal".......and that "meal" could be fish n chips, steak and chips, or pizza...........and you want the pizza.......so you place your order and hope that you get a pizza.....but along comes the waiter with your meal.....and its fish n chips.

Tough.

Thats whats happening in the LED industry.

i guess you have to walk round the restaurant with your plate of fish and chips, and see if you can find someone with a pizza who didnt want it, and try and do a swap......is it crazy?..or is it just me?.....maybe the restaurant didnt want to get lumbered with a freezer full of the most unpopular food?

Does anybody know if Cree, Philips, Avago and dialight also operate in this way?