SMD Packages explained!. The Funkiester writes (again!) –

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.