The NCP108x integrates a Power-over-Ethernet (POE) interface with a DC-DC controller, reducing the BOM for a POE implementation. However, DC-DC convertor design is not always easy, especially considering the many EMC and EMI pitfalls. Testing often reveals that a convertor design radiates more electromagnetic charge than is allowed by regulations. Read this document to learn tips and guidelines on building a power supply design that can pass these tests.