电子元器件日益增长的复杂性提高了对元器件封装的引脚数量要求,从而导致了SMD的引入和推广,SMD为提供所要求的I/O数量而具有越来越细的引脚间隔。另外,许多公司通过设计出两面都有有源器件的电路板来提高密度。这种设计 The growing complexity of electronic components has raised the pin count requirements for component packaging, resulting in the introduction and promotion of SMDs with ever-finer pin intervals to provide the required I / O count. In addition, many companies increase their density by designing circuit boards that have active devices on both sides. This design