电路板的焊盘设计（Pad design of circuit board）.doc

电路板的焊盘设计（Pad design of circuit board） Pad design of circuit board Classification: Analog Design | 2008-05-28 Power line | Author: Shenzhen Nanshan District city Kiev electronic products trade Pad (land), a basic unit of surface mount assembly, that is used to form a pattern (land) of a circuit board, i.e., a variety of pad assemblies designed for special component types. Nothing is more frustrating than a poorly designed pad structure. When the design of a pad is not correct, it is difficult and sometimes impossible to achieve the desired welding point. The pad English has two words: Land and Pad are often used interchangeably; however, in function, Land is a two-dimensional surface features, can be used for surface mount components, while Pad is a three-dimensional features, can be used for plug-in components. As a general rule, Land does not include plated through holes (PTH, plated, through-hole). The bypass hole (via) is an electroplating through hole (PTH) that connects different circuit layers. The blind bypass (blind, via) connects the outermost layer with one or more inner layers, while the buried bypass hole is connected only to the inner layer. As noted above, pad Land usually does not include plated through holes (PTH). A PTH in the pad Land will take a considerable amount of solder during soldering and, in many cases, lead to solder defects. However, in some cases, component wiring density forces this rule to change, and most notably, for chip scale packages (CSP, chip, scale, package). It is difficult to wire a wire through a labyrinth of pads below the 1.0mm (0.0394) pitch. A blind bypass hole and a micro bypass hole (microvia) are produced in the solder plate, allowing direct routing to the other layer. Because these bypass holes are small and blind, they do not absorb too much solder, resulting in little or no solder impact on solder joints. There are a lot of industrial literature for IPC (Association Connecting Electronics Industries), EIA (Electro