What this 220 nH drum-core inductor is for
The Murata LQH31MNR22K03L is a 220 nH drum core wirewound inductor in the LQH31 series, built on a ferrite core with an unshielded construction. Rated for 240 mA DC with a maximum DC resistance of 602 mOhm, it is sized for low-current power rail filtering, decoupling, and RF bias-T applications where the 250 MHz self-resonant frequency gives useful inductive behavior up through VHF.
Last Buy — what it means for your BOM
Murata has flagged the LQH31MNR22K03L as Last Buy — the manufacturer is ending production, and this is the final procurement window before the part becomes unavailable through authorized channels. For an existing BOM line, the practical path is to secure lifetime-buy stock now or qualify a substitute inductor with matching inductance (220 nH ±10%), current rating (≥240 mA), and 1206 footprint.
Key ratings and the fit decision
The 220 nH ±10% inductance at 1 MHz test frequency is the primary selection parameter — it sets the resonant frequency in an LC tank or the corner frequency in a pi-filter. 240 mA current rating is the DC bias limit before the ferrite core saturates and inductance drops; derate for ambient temperature above 85°C. 602 mOhm max DCR produces an I²R loss of about 35 mW at full rated current — negligible for most circuits but worth checking if the inductor sits in a high-side supply rail where the voltage drop matters. A Q factor of 20 at 25 MHz is moderate — adequate for broadband filtering and decoupling, but not for a narrowband resonant circuit where a higher-Q part would reduce insertion loss. The unshielded construction means the magnetic field fringes outside the core — keep sensitive analog traces or other inductors at least one body width away to avoid coupling.