12 µH ferrite-core inductor for DC-DC input/output filtering
The LQH2MCN120K02L is a 12 µH unshielded wirewound inductor from Murata's LQH2 series, built on a ferrite drum core. It is rated for 210 mA continuous current with a maximum DC resistance of 1.82 Ohm — the DCR sets the I²R conduction loss and temperature rise in the winding, so at full load the inductor dissipates roughly 80 mW internally, which the 0806 package sinks into the board copper. The self-resonant frequency is 44 MHz, meaning the inductor behaves inductively up to that point; above 44 MHz the parasitic capacitance between windings dominates and the impedance rolls off. For a buck converter switching at 1–4 MHz, the 12 µH value and 44 MHz SRF leave plenty of margin before the inductor self-resonates.
Package fit and rework on the bench
The unshielded construction means there is no magnetic shield layer — the flux field extends beyond the body, so keep a clearance of at least one part width from adjacent GND planes or sensitive traces to avoid eddy-current losses and coupling. The ferrite core and wirewound construction handle a standard reflow profile well — the body is not moisture-sensitive in the way a ferrite bead is, so no special bake-out is needed for typical floor life. The ±10 % tolerance on the 12 µH value is the standard Murata bin; if the DC-DC loop compensation is tight, confirm the inductance at the bias current (the ferrite permeability drops with DC bias, reducing effective L).