Simple Success with Conducted EMI and Radiated EMI for LMR160X0

Electromagnetic Interference (EMI) is an unwanted effect between two electrical systems as a result of either electromagnetic radiation or electromagnetic conduction. EMI is the major adverse effect caused by the application of switch-mode power supplies (SMPS). In switching power supplies, EMI noise is unavoidable due to the switching actions of the semiconductor devices and resulting discontinuous currents. EMI control is one of the more difficult challenges in SMPS design, beyond functional issues, robustness, cost, thermal and space constraints. First, this application note introduces the overview of LMR160X0 family products and conducted EMI knowledge. Second, step by step differential filter parameters design will be introduced to suppress conducted EMI noise. Third, a reference PCB layout based on LMR160X0 is presented. Finally, both conducted EMI and radiated EMI test with and without input filter were provided and compared to verify the theories. This approach also could be applied to the LMR140X0 family.