Drum core wirewound, 1.5 µH, 500 mA — what the ratings mean for a BOM line
The LQH43NN1R5M03L is a Murata drum-core wirewound inductor in the LQH43 series, unshielded, with a ferrite core and a 1.5 µH inductance at ±20% tolerance — the loose tolerance is typical for power-grade inductors where the DC bias current dominates the effective inductance drop. Rated for 500 mA continuous current with a maximum DC resistance of 300 mOhm — at full rated current the self-heating from I²R losses is about 75 mW, which is well within the 105°C operating limit for a standard 1812 footprint on a two-layer board. Self-resonant frequency is 85 MHz, so this part is usable as a power-supply filter inductor well into the tens of MHz before the parasitic capacitance turns it capacitive — fine for DC-DC converter output stages switching at 1–2 MHz.