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本文概述了SMT的发展过程,详细阐述了它的优点。指出它是目前减小体积和重量的最有效的方法。为便于比较起见,把SMT贴装板和目前常用的插装板举例作了比较。若采用两面安装,SMT所需的板面积只有插装板面积的1/3。随着SMT技术的发展,适合于这项技术的各种元件,如无源元件(电阻、电容和电感)和有源元件(SOIC和QEPIC)也都朝着片状、小型化方向发展,文中示出了这两种元件的相应尺寸。介绍了目前常用的三种SMT的优缺点,示出了它们的工艺流程图。并对组装过程中出现的工艺问题(如引线平整度、可焊性等)进行了详细分析。最后给出SMT的设计规范,以及SOIC和PLCC的样板尺寸,这是关系到高性能、高密度、高成品率的重要因素。
This article outlines the development of SMT and details its benefits. Pointed out that it is currently the most effective way to reduce size and weight. For the sake of comparison, the SMT mounting board is compared with the currently used mounting board. If the use of two-sided installation, SMT board area required only one-third of the board area. With the development of SMT technology, various components suitable for this technology, such as passive components (resistors, capacitors and inductors) and active components (SOIC and QEPIC), are also developed in the form of chips and miniaturization. The corresponding dimensions of these two elements are shown. Describes the advantages and disadvantages of the three commonly used SMT, showing their process flow chart. And the process of assembly process problems (such as lead flatness, weldability, etc.) were analyzed in detail. Finally, given the SMT design specifications, as well as SOIC and PLCC sample size, which is related to high performance, high density, high yield an important factor.