• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Packages

wuchy143

Member
Thanks for the reply. Yes you are correct. I do mean the PLCC-4 and it does relates to my other post.

I am converting all my LED's to SMT and I don't want to pick a package which will be hard to find a certain type of LED because I do a lot of custom designs. It would be bad later down the road spinning a board just because I don't have the right package for say a, "purple" led which isn't too common.
 

Mickster

Well-Known Member
I don't know whether this needs to be continued here, or in the other thread, but here goes...

For single colour PLCC LEDs, the most common package seems to be PLCC-2, but for reasons unknown to me, I have also scavenged some single colour PLCC-4's.

PLCC_4_2_a.PNG
PLCC_4_2_b.PNG

In both attached images, the left LED is PLCC-4 and the right is PLCC-2. As you can see, they are both the same physical size and only have one die, but the -2 & -4 denotes the number of solder points. Why a single colour LED is available in a PLCC-4 package....I don't know, but I'm digressing. Maybe someone else can clarify.

Also, your requirement of around 3000mcd and an SMD device roughly 0.18" x 0.18" (4.5mm x 4.5mm) or smaller, seems to be quite scarce within the results returned from a quick search here:
Optoelectronics and Displays | Optoelectronics | Visible LED

Can you provide a little more detail with regard to the design requirements?

This will likely get much more helpful replies, from those in a better position to help.

Regards.
 

wuchy143

Member
Hi Mickster,

Thanks for the info. It is a little odd that there is very little difference b/t the two packages. Perhaps the plcc-4 is for mechanical stability. I have seen them used in high end cars for turn signals..etc. Granted that is just a thought. Not sure the real reason if there is one.

My application is for a capacitive touch switch. If you look at the attached file you will see the copper pads used on my boards and in the middle of the "donut" is where I currently install a T1 thru-hole LED. Basically a metal foil comes down and creates two caps in series resulting in less capacitance. This change in voltage is read by hardware and sent to an 8051. I use 3,000MCD, 30 degree angle, LEDs currently which provides enough light to shine up through the switch(it's clear) and hit the light pipe.

I'd like to have .010" clearance on each side to not short the leads of the LED and the capacitive copper pads. This is why I need such a tiny LED. I guess the better question for me to ask is what is the most common package tiny SMT LED?

Again thanks!!

-mike
 

Attachments

Last edited:

Mickster

Well-Known Member
I suppose the main questions to be asked, are:

How brightly does the switch need to be illuminated, to have the requirement of a 3000+mcd LED?

Does it need to be highly visible in a well lit environment, or visible from great distances, etc?

The reason for asking such questions is, if you just need a simple on/off visual indicator for the switch, 3000mcd seems to be pretty high and maybe the LED distance/location to the light pipe is the problem, but we don't know what switch you are using or how brightly it needs to be illuminated.

An example:
On the Xbox 360 controller, there are 4 green LEDs around the Guide Button (on/off/menu) which indicate the Player No using the controller - P1 to P4.
These LEDs are an 0603 package, 0.063" × 0.031" (1.6 mm × 0.8 mm).......... a little smaller than the size of a pinhead.
I don't know the exact value used by Microsoft, but would guess from the available replacements phenoptix items - Get great deals on items on eBay.co.uk Shops! that they may be in the ballpark of 500mcd. (I have no relationship with that ebay link, other than that of a satisfied customer. Due to their miniscule size, they are quite tricky to handle and solder manually.)
The 0603 LED and light pipe setup used, is quite sufficient to easily be seen at least 10 feet away.

Common packages of SMT LEDs?
In order of size (larger to smaller) - PLCC, 1206, 0805, 0603 and perhaps 0402 becoming ever more popular as devices continue to shrink!!

HTH.

EDIT:
This is an 0402 package - http://www.globalspec.com/FeaturedProducts/Detail/Kingbright/0402_SMD_LED/4017/0
 
Last edited:

wuchy143

Member
We use T1 LED's for our currently backlit products which works perfectly. All it is doing is lighting up a keyboard key. So, the light comes up through the switch, goes through a light pipe and all the light hits a lazered plastic key. See the attachment. We have found after much research that the 3000 MCD @30 degree angle gives us the best splash on the keys given our mechanical set-up and dealing with silicone raincoats and all that junk in the way of the light.

Good Xbox example. Kinda made me want to go play some MW2 :) I'd agree on them being hard to handle manually. We are getting a SMT line soon so this design is my attempt to change all our technology over to SMT. The LED's are obviously just one wrinkle in this task. We are also modularizing everything which is where the real work is.

Ultimately I'm trying to find a common smt package, that is rougly the same price as our current T1 LED's which range from 10 cents a LED to about 30 cents for our blue ones. I'm replicating the data from our T1 LEDS(angle, MCD, etc) because they currently work great and serve as a good first order approx. of what I'm trying to achieve.

I'm leaning towards teh PLCC-4 or 2. I guess whichever I can get more readily and cheaper I'll go with. Thanks for your help.

-mike
 

Attachments

Latest threads

EE World Online Articles

Loading

 
Top