1.5 mH wirewound inductor for filtering and energy storage
The Murata LQH43NN152J03L is a drum core, wirewound inductor in the LQH43 series, rated 1.5 mH ±5% with a 40 mA DC current rating. The 37 Ohm maximum DCR sets the I²R loss floor — at 40 mA the self-heating is about 59 mW, negligible for most filter stages, but the DCR matters for series-pass applications where the voltage drop across the inductor must stay within the rail budget. The unshielded ferrite core construction means the magnetic field extends beyond the component body — keep sensitive traces or low-level analog circuits at least one part-width away to avoid coupling. The 1.6 MHz self-resonant frequency (SRF) is the upper bound for useful inductance; above SRF the part behaves capacitively, so it suits DC-DC converter output filters and EMI suppression below 1 MHz.
Q factor and frequency response for tuned circuits
A Q factor of 40 at 252 kHz tells you the inductor's reactance-to-resistance ratio at that test frequency — high enough for resonant tank circuits in LC oscillators or bandpass filters where selectivity matters. Below 252 kHz the Q drops as the core losses increase; above it the winding AC resistance rises with skin effect, so the peak Q sits near the test point. The inductance is tested at 1 kHz, a standard low-frequency reference point. At the SRF (1.6 MHz) the effective inductance has already rolled off; for a filter designed at 100 kHz, expect the actual inductance to be within a few percent of the 1.5 mH nominal, but always verify with the impedance curve from the full datasheet if the operating frequency approaches 500 kHz.