8.2.2.1.1 Inductor Selection

DC bias current characteristics of inductors must be considered. Different manufacturers follow different saturation current rating specifications, so attention must be given to details. DC bias curves should be requested from manufacturers as part of the inductor selection process. Minimum effective value of inductance to ensure good performance is 0.33 μH at maximum load current over the operating temperature range of the inductor. The DC resistance of the inductor must be less than 0.05 Ω for good efficiency at high-current condition. The inductor AC loss (resistance) also affects conversion efficiency. Higher Q factor at switching frequency usually gives better efficiency at light load to middle load. See Table 7. Shielded inductors are preferred as they radiate less noise.