4.7 µH at 500 mA — DC bias and power rail filter fit
The LQH43MN4R7K03L is a 4.7 µH drum core wirewound inductor rated for 500 mA continuous current. At that DC bias the 400 mOhm maximum DCR drops about 200 mV and dissipates 100 mW — well within the 85°C ambient limit for a ferrite-core part in a 1812 footprint. Its 38 MHz self-resonant frequency means the inductor behaves inductively up to about 10–15 MHz in practice; above that the winding capacitance starts to dominate. For a buck converter switching at 1–2 MHz the SRF gives plenty of margin.
Unshielded construction — layout awareness
This is an unshielded drum core (ferrite core, wirewound on a bobbin). The stray magnetic field extends beyond the component body — keep sensitive analog traces, RF front-ends, or other magnetics at least 3–5 mm away on the same layer. The Q factor is 30 at 1 MHz, a moderate figure typical of ferrite-core wirewounds in this size. The AC resistance at the switching frequency will be higher than the 400 mOhm DC value; budget the additional copper loss if the ripple current is a significant fraction of the 500 mA rating.
1812 SMD footprint and temperature grade
Standard reflow profile for a ferrite-core part — no special bake-out required unless the tape has been exposed to high humidity. The ferrite core material is stable across this range; the inductance shift with temperature is typically less than ±5%.