Active production — 220 µH unshielded inductor for general-purpose filtering
The Murata LQH43MN221J03L is an active-production drum core wirewound inductor in the LQH43 series, rated 220 µH ±5% with a 110 mA current rating and 5.4 Ohm maximum DCR. The 1812 (4532 Metric) surface-mount package and ferrite core suit it for DC-DC converter output filtering, EMI suppression, and signal-line decoupling where the 110 mA ceiling and 5.4 Ohm series resistance are within the loss budget.
Q factor, self-resonant frequency, and usable band
A minimum Q of 40 at 796 kHz and a self-resonant frequency of 4.5 MHz mean the inductor maintains useful Q up to a few MHz — above that the parasitic capacitance dominates and the impedance rolls off. The 1 MHz test frequency for the inductance value sits well below the SRF, so the 220 µH figure is representative in the low-MHz switching range typical of small DC-DC converters.