820 µH at 50 mA — the parametric corner
The LQH43NH821J03L is a drum-core wirewound inductor from Murata's LQH43 series, rated 820 µH at 1 kHz test frequency with ±5% tolerance. Its 50 mA current rating is paired with a 17.4 Ohm maximum DCR — the DC resistance dominates the I²R loss and sets the self-heating budget in this package. AEC-Q200 qualification means this part passed automotive-grade stress tests including thermal shock, vibration, and solder heat resistance per the AEC-Q200 passive-component specification.
1812 footprint and unshielded construction
The unshielded construction means magnetic flux radiates from the core; adjacent traces carrying sensitive analog signals or high-speed edges need keep-out spacing to avoid crosstalk coupling. Supplied on tape-and-reel in cut-tape quantities — standard pick-and-place handling for the 1812 size, no special nozzle required.
Q factor and self-resonant behaviour
Q factor is 40 at 796 kHz — the ratio of inductive reactance to effective series resistance at that frequency, indicating moderate selectivity for filter applications in the low-MHz band. Self-resonant frequency is 2.2 MHz; above this point the inductor behaves capacitively, so the part is suited for DC-DC converter switching frequencies up to roughly 500 kHz where the impedance curve remains inductive.