18 µH, 340 mA — the DCR sets the current ceiling
The LQH43NN180K03L is a Murata drum-core wirewound inductor from the LQH43 series, rated 18 µH ±10% at 1 MHz test frequency. Its 340 mA current rating is paired with a 820 mOhm max DC resistance — the DCR is the limiting factor for continuous current, not core saturation, so the temperature rise under load is what governs the real-world derating. Unshielded construction means the magnetic field extends beyond the component body — keep a clearance zone around adjacent traces or other inductors in a power filter stage to avoid coupling.
Q factor and self-resonant frequency — bandwidth limits
Q factor is 35 at 1 MHz, and the self-resonant frequency is 17 MHz. Below about 5 MHz the impedance is inductive and useful for filtering; above that the parasitic capacitance starts to dominate and the inductor behaves capacitively. For a DC-DC converter switching at 1–2 MHz, this part stays well within its inductive region. Ferrite core material gives stable inductance over temperature within the -40 to 105 °C operating range — no significant drift until approaching the Curie point of the ferrite, which is well above 105 °C.
Active lifecycle — no obsolescence watch needed
It is a standard catalogue part in the LQH43 series, available through distribution channels. Store the reels in a dry environment; the part is not moisture-sensitive per Murata's standard handling, but the reel packaging benefits from <60% RH storage.