What is surface mounting?
Simply talking surface mounting is a soldering technology where the component is soldered directly to a series of solder pads called a footprint. It is different soldering technology from through-hole, where component leads are inserted into holes of the board. The footprint is a series of pads that conform to the lead layout of packages of surface mount devices (SMD). Surface mounting has several advantages over through-hole technology. First of all the board become much smaller. So smaller boards and more dense placement of elements reduce costs. Because of higher placement density, traces between components becomes shorter. It lowers parasitic inductance and capacitance.