2.2 µH drum-core inductor for power rail filtering
The Murata LQH43CN2R2M03L is a 2.2 µH drum-core wirewound inductor in the LQH43 series, built on a ferrite core and rated for 900 mA continuous current with a maximum DC resistance of 110 mOhm. The 1812 surface-mount footprint (4.50 mm × 3.20 mm) fits standard pick-and-place assembly, and the unshielded construction means magnetic flux radiates from the component — keep sensitive traces or adjacent inductors at least one body width away to avoid coupling.
Current rating, DCR, and self-resonant frequency
The 900 mA current rating is the saturation-limited continuous current at 25°C ambient; above this the inductance rolls off as the ferrite core approaches saturation. For a 12 V to 5 V buck converter at 500 kHz switching, this inductor handles output loads up to about 800 mA with 20-30% ripple current before the core losses dominate. 110 mOhm DCR generates I²R losses of 89 mW at full rated current — negligible for most designs, but in a high-density board the self-heating adds 5-10°C above ambient, so derate the current by 10% per 10°C above 70°C ambient. The self-resonant frequency of 60 MHz sets the upper frequency limit where the inductor behaves as an inductor rather than a capacitor. Below 20 MHz the impedance is inductive and useful for switching regulators and EMI filtering; above 60 MHz the parasitic capacitance dominates and the component becomes a low-impedance path.
Active lifecycle and sourcing posture
The 1812 package and 2.2 µH value are common enough that a second-source alternative from another manufacturer (e.g., TDK or Würth) can be qualified in parallel for dual-source risk reduction.