47 µH shielded power inductor for DC-DC input/output filtering
The Murata LQH32PB470MN0L is a 47 µH shielded wirewound inductor in the LQH32 series, built on a ferrite drum core with a ±20% tolerance. It carries a continuous current rating of 310 mA and a saturation current floor of 330 mA — the point where inductance drops by roughly 30%. The self-resonant frequency of 11 MHz means this inductor behaves inductively up to that point; above it, parasitic capacitance dominates and the impedance rolls off.
Current rating and saturation — the two numbers that govern the load
The 310 mA current rating is the DC bias at which the temperature rise stays within the part's design limit. The 330 mA saturation current (Isat) is the hard ceiling where the inductance drops by 30% — a DC-DC converter running near Isat sees ripple current spike and output voltage ripple increase. For a buck converter switching at 1 MHz (the test frequency), the 47 µH value sets the inductor ripple current at about 30% of the load current for a typical 12 V to 3.3 V conversion, keeping the converter in continuous conduction mode. The shielded construction contains the magnetic flux within the core, reducing EMI radiated to adjacent traces and components — important when the inductor sits near a sensitive analog front-end or RF section on the same board.
Operating temperature range and deployment context
The ferrite core material maintains its permeability across this range, though DC bias saturation current derates at elevated temperatures — a factor to budget when the inductor shares a hot PCB with a regulator or processor.