Component identity and key parametrics
The Murata LQH43MN681J03L is a drum-core, wirewound inductor from the LQH43 series, specified at 680 µH with a ±5% tolerance. It is an unshielded part, so the magnetic field extends beyond the component body — keep sensitive traces or adjacent magnetics at least one body width away to avoid coupling. Rated for 65 mA continuous current with a maximum DC resistance of 17 Ohm. The 65 mA ceiling is the thermal limit at 85 °C ambient — derate linearly above 70 °C if the board sees sustained airflow below 0.5 m/s. Self-resonant frequency is 2.5 MHz, and the Q factor measures 40 at 796 kHz. Above 2.5 MHz the inductor behaves capacitively — not useful as a filter element past that point.
The ferrite core and wirewound construction mean the part is heavier than a multilayer chip inductor of the same footprint — verify solder-paste volume on the reflow profile to avoid tombstoning. Operating temperature range is -40 °C to 85 °C, which covers industrial and automotive cabin environments but not under-hood or engine-bay zones. The part is unshielded, so a pick-and-place nozzle with a soft tip is recommended to avoid cracking the ferrite body during placement.