1.8 µH drum core for DC-DC filtering
Murata LQH43MN1R8M03L is a fixed 1.8 µH drum core wirewound inductor in the LQH43 series, surface-mount in an 1812 (4532 metric) package. Rated for 500 mA DC with a maximum DCR of 300 mOhm — the resistance sets the I²R heating floor, so the actual current ceiling in a 85 °C ambient is lower than 500 mA unless the board copper pulls the heat away. Unshielded construction means the flux field extends beyond the body — keep sensitive traces or another inductor at least one body-width away to avoid coupling.
SRF and Q factor at 1 MHz
Self-resonant frequency is 75 MHz — above that the part behaves capacitive, so it filters cleanly up through the low-VHF band for SMPS output ripple or signal decoupling. Q factor is 20 at 1 MHz test frequency, typical for a ferrite-core drum in this inductance range; the Q peak is usually above 10 MHz and the roll-off starts well before the SRF.