DC-DC Buck Converter EMI Reduction Using PCB Layout Modification

The paper treats the effect of layout on the electromagnetic interference (EMI) of buck converters. An optimized layout design for dc-dc synchronous buck converter is proposed for EMI reduction. Six different layout versions are analyzed with respect to loop area, loop inductance, radiating dipole moments, and far-field radiation. Optimizations are done with respect to field-effect transistor (FET), decoupling capacitor and via placement. Passive full-wave simulations are used to estimate and verify the loop inductance and far-field emissions. Those are compared with measurements. A gigahertz transverse electromagnetic (GTEM) cell is used to quantify the dipole moments in the printed circuit board (PCB) for estimating the far field and comparing to measurement.