When designing an electronic circuit it is necessary to take a number of precautions to ensure that its EMC performance requirements can be met. Trying to fix the EMC performance once the circuit has been designed and built will be far more difficult and costly. There are a number of areas that can be addressed during the circuit design and PCB layout stage to ensure that the EMC performance is optimized:-PCB Circuit design -PCB Circuit partitioning-PCB Grounding-PCB Routing-EMC Filters-I/O Filtering and ShieldingBy adopting these precautions, the EMC performance of PCB layout can be greatly enhanced.