What the 2.1 A rating means for your power rail
The LQH43CN2R2M33L is a drum-core wirewound inductor in the LQH43 series, rated 2.2 µH at 1 MHz test frequency with ±20% tolerance. The 2.1 A current rating is the DC current at which the inductance typically drops by 10% due to core saturation — not the thermal limit. At that bias point the actual in-circuit inductance may sit around 1.8 µH, so your ripple current and transient response calculations need to use the saturated value, not the nominal open-circuit number. The 61 mOhm max DCR sets the I²R conduction loss at 0.27 W at full rated current.
Footprint and placement constraints
The unshielded construction means the magnetic field radiates from the drum core — keep sensitive analog or RF traces at least 5 mm away on the same layer, and avoid placing it directly under a ferrite-bead-filtered supply rail on the opposite side of the board. The self-resonant frequency is 60 MHz. Below that frequency the part behaves as an inductor; above it the impedance becomes capacitive. For a buck converter switching at 1-2 MHz, the 60 MHz SRF is well clear of the switching harmonics, so the inductor maintains its inductive character across the relevant frequency range.
Sourcing status and procurement posture
No pin-compatible second-source is documented in the family, so the BOM line is single-sourced to this Murata order code.