一款485通讯隔离产品的EMC设计与改善

电子、电气产品的设计，必须保证在一定的电磁环境中能正常工作，既满足标准规定的抗干扰极限值要求。在受到一定的电磁干扰时，无性能降级或故障；又要满足标准规定的电磁辐射极限值的要求，对电磁环境不构成污染。所以，产品设计之初，就要从分析产品预期的电磁环境、干扰源、耦合途径和敏感部件入手，采用相应的技术措施．抑制干扰源、切断或削弱耦合途径，增强敏感部件的抗干扰能力等。文中详细介绍了一款485通讯隔离产品从辐射超标到顺利通过FCCCLASSB认证，在原理设计、PCB制板等多方面所做的各项改进措施。文中所提到的方法及规则．对产品EMC设计具有很大的参考及指导意义。

EMC design and improvement of a RS-485 isolated communication product

At the beginning of the product design, it is necessary to start from analyzing the electromagnetic environment, source of interference coupling path and sensitive components. And then apply appropriate technical measures to curb the sources of interference, to cut or weaken the coupling path, and enhance the anti-interference ability of the sensitive components. This paper describes how a communication isolated product passed FCC CLASS B certification. Mentioned methods and rules about the schematic and PCB have great reference and guidance.