Editor's Note: This column originally appeared in the July 2012 issue of SMT Magazine.

Amazing, isn’t it? For a little less than $500 you can buy a high-end smartphone that serves as an all-in-one device. Integrated communication (voice calling, e-mail, Skype, SMS, Twitter), information (PDA, radio, navigation, Internet), and entertainment (camera, gaming, media player) can all be found in a housing slightly larger than a pack of cards with the thickness of a glossy magazine.

The most important enabler is miniaturization. Miniaturization brings more functions in the same size, or the same functions in a smaller size. Take a look inside your smartphone. Teardown websites will show thin and flat subassemblies, small-sized and high-density populated substrates, and large-area thin battery packs.

Miniaturization continues to grow in importance, not only for smart phones (Remember, we want them to fit in our pockets!), but also for medical implants like hearing aids and pacemakers. And we want our tablet PC and LED TV to be as thin as possible.

Of course, integrated circuits (ICs) will continue to integrate more devices, but the great majority of components on a PCB are passives. At board level, the next round of miniaturization will come from the three key factors that follow.

Reducing Component and Substrate Line Interspacing

A large number of components per board area translates to minimizing component size and related interspacing. Some years ago, the smallest passive component in handheld products was the 0201 (0.6 mm x 0.3 mm). Now it is the 01005 (0.4 mm x 0.2 mm), with leading passive component manufacturers having recently introduced 0.3 mm x 0.2 mm components, and 0.2 mm x 0.1 mm types expected later this year.