09-11-2012, 02:21 PM
Surface mount technology (SMT)
Introduction
Surface mount technology (SMT) is a method for constructing electronic circuits in which the components (SMC, or Surface Mounted Components) are mounted directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface mount device or SMD. In the industry it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board.
Advantages
Smaller components. Smallest is currently 0.2 x 0.1 mm. (.01" x .005": 01005)
Much higher number of components and many more connections per component.
Fewer holes need to be drilled through abrasive boards.
Simpler automated assembly
Disadvantage
The manufacturing processes for SMT are much more sophisticated than through-hole boards, raising the initial cost and time of setting up for production.
Manual prototype assembly or component-level repair is more difficult (more so without a steady hand and the right tools) given the very small sizes and lead spacings of many SMDs.
Applications
In making PCBs which are use in every electronic device.