What the 100 µH and 150 mA rating mean for your filter or DC-DC stage
The LQH43NH101J03L is a 100 µH drum-core wirewound inductor from Murata's LQH43 series, rated for 150 mA continuous current with a maximum DC resistance of 2.4 Ohm. In a buck converter output filter, the 100 µH value sets the inductor ripple current — at a given switching frequency and input voltage, higher inductance means lower ripple, but the 2.4 Ohm DCR will drop 360 mV at full rated current, so the downstream rail needs headroom. The 150 mA rating is the DC bias current at which the inductance typically drops by 10%; stay below this to keep the filter corner frequency stable.
The ferrite core material maintains inductance across this band, though the DCR will drift with temperature per the copper winding's positive coefficient.
The unshielded construction means magnetic flux radiates from the core — keep sensitive analog traces or low-level signal routing at least one package width away to avoid coupling. The tape-and-reel packaging supports automated pick-and-place; the cut-tape option works for prototypes or small-batch builds.
Self-resonant frequency and Q factor — where the inductor behaves like an inductor
The self-resonant frequency (SRF) is 6.8 MHz. Above this frequency the parasitic capacitance between windings dominates and the component behaves capacitively — so for a 100 µH inductor, the useful range for filtering or energy storage tops out around 1-2 MHz. The Q factor is 40 at 796 kHz, which is the test frequency for the Q spec; at that point the inductive reactance is roughly 500 Ohm, and the equivalent series resistance from core and winding losses is about 12.5 Ohm.