SMD Packages explained!

Hello! Well as a result of all the great feedback from the component packages, I’m doing another post about SMD packages!  I may be using some of the terminology from the last post in here as well, so just in case, here is the last post

First off, SMD means Surface Mount Device; There is another acronym used that means pretty much the same thing which is SMT, and that means Surface Mount Technology.  This’ll be describing the various packages that an LED can come in, as well as resistor and the more common capacitor packages as well as many other surface mount devices.  The big rule about SMD is that many packages are represented by a 4 digit code.  The first two digits indicate its length and the second two digits indicate its width.  So an 0603 package would be .06″ x .03″ .  Although if it isn’t represented by a 4 digit code, that doesn’t mean that it isn’t an SMD component, all that means is that you’ll have to do a little more searching to find the dimensions of your specific component.

The most common packages are the: 0603 , 0805 , 1206, 2512,  and the SOT. although we will be discussing the 0606, 1204, 1210, SOD, PLCC, Chimney-Type, 3528, 5050, A, C, D, E.  The space on the board where the SMD will sit is called the footprint, and the footprint is like a little diagram as to where the component is to be soldered on the board and how much space it takes up.

More common:

To start off, the 0603!  The 0603 has the dimensions of .06″ x .03″ and has the contacts to be soldered on each end of the component.  This package is the most common as it is small and very straight forward to put on.  It always has 2 leads on the underside or the ends, unless it is an extremely special component.  The 0603 is used for LEDs, Capacitors, Resistors, Thermosistors, Varisistors, Fuses, Inductors, Chokes, a few IC’s.  There are some other kinds as well, I only listed the ones that digi-key had over 500 items of.

Next, 0805! It is .08″ x .05″ and the footprint is the same as the 0603, which also means that the contacts to be soldered are in the same place as well.  The 0805 can be used for the same applications as the 0603 although it is larger, obviously, and as a result is usually used for applications that require a little more “oomph” , like a larger capacitor value than an 0603 can offer.  But other than that, it’s pretty much the same.

1206: The dimensions of this are .12″ x .06″, this means it is a little longer but not much wider then the previous packages.  Although in terms of difference, there isn’t much.  Basically just a size up from the 0805.  Footprint and usage is the same with regards to the size.

The 2512 is .25″ x .12″ and is quite similar to the others.  One of the more noticeable differences is that it is actually a little thinner than the previous listed.  The 2512 is mostly used for capacitors and resistors, and not so much LED’s.  Although that doesn’t mean it can’t happen, the 2512 package is just a bigger version of the previous packages.

The SOT package stands for Small Outline Transistor.  Although this one uses “gull-wing” leads, rather than the leads like the ones before. The most popular out of this package is the SOT-23 which generally will have 3, 5, or 6 leads.  Keep in mind these leads come out of chip, unlike the previous SMD packages.  Seeing as how this package is centered around transistors, that’s mainly what it is used for.  Zener diodes, rectifiers, field-effect transistors, RF diodes, and many other various transistors, along with switch IC, amplifier IC, buffers, gates, and inverters, LED Drivers, voltage regulators, temperature sensors, and transducers.  The list can still go on and on.  If you haven’t noticed already, this package is rarely used for resistors, so don’t expect that.

The 3528 package is pretty similar to the 5050 in terms of what it is used for.  It is .35″ x .28″ and it will usually house a single LED.  That is the big difference between the two.  3528 has one led, 5050 will have 3.

The 5050 package is .5″ x .5″ and is used for High Brightness, Bi-color, and RGB LEDs and I personally love it!  The footprint is a square and the package will generally have 6 leads that get soldered to the board.

Less common:

The others will start with the 0606.  It has the .06″ x 06″ dimensions and is the first of ours listed to be a perfect square.  These are more widely used for bi-color or tri-color SMD LED’s, although they are also used for ceramic capacitors, chip resistors, and a few simple logic gates.  Seeing as how they aren’t as common, it is normal for their to be less typical options for this package.  Footprint is still similar to the ones before.

The 1204 package is .12″ x .04″ and has a similar footprint to the others.  This is sometimes called the Right-Angle SMT package mainly because it’s a package that has the component at a right angle to the board.  That is the norm for this package although it can also be normal and have it on the bottom like the others.  Because of the right-angle reputation of this package, it is almost strictly used for LEDs with a rounded lens, but there are some chip resistors that use this package.

1210: this package is .12″ x .1″ and is used for various capacitors such as ceramic, tantalum, Mica, and PTFE, as well as re-settable fuses, inductors, coils, chokes, a few LED’s, and thousands of resistors.  It sorta looks like a little box.  Like before, the footprint is still similar to all the others.

SOD: a lesser common package than the even less common, is the Small Outline Diode which, by the name, is mainly used for diodes. It is also used for rectifiers and zener diodes.  That’s about it.  The footprint for this component is very similar to the others although the leads come out of the component just a tad.

The PLCC is the Plastic Leaded Chip Carrier, and I’ve mentioned this before, and the full description can be found in my other post that is linked at the top.  I wanted to mention it again because I never did say that it could be surface mounted too.  Well it can!  You would generally get a socket for development, although if you are making a final product for manufacturing, you would solder this chip directly onto the board and it would still work fine.

The Chimeny-Type: LED’s are accepted to be the only use for this package.  It is a right-angle SMT although the leads aren’t just on the component, they come out and it almost resembles a through-hole component but with the leads bent a little bit.  As you can see in the picture, it works great for 3mm LEDs.  This is pretty rare, actually.

The A,C,D, and E packages are mainly for capacitors, specifically Electrolytic.  These packages aren’t very common among all components, although expect to see them when looking for surface mount capacitors.  There are some other packages like V and H.  The A package starts at 10V and then the E goes to 25V so the rest are in between.

So that’s that! There are more packages out there, I describe some of the more common ones.  If you’d like to do some more research, here are a few links:

Footprints : http://www.siongboon.com/projects/2005-09-07_home_pcb_fabrication/footprint/index.htm

Overview of many SMD packages : http://www.radio-electronics.com/info/data/smt/smt_packages.php

Surface mount soldering tutorials: http://www.sparkfun.com/tutorials/category/2

You stay classy, I’m The Funkiester?

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