22 µH wirewound — what the ratings mean for the BOM line
The LQH43NN220J03L is a 22 µH unshielded wirewound inductor from Murata's LQH43 series, built on a ferrite drum core. The 320 mA current rating is the DC bias at which the inductance typically drops by 10% — staying below this keeps the filtering or energy storage characteristic stable. The 940 mOhm max DCR means I²R losses hit about 96 mW at full rated current, a figure that matters for thermal budgeting in a dense SMD layout.
Q factor and self-resonant frequency — frequency-domain fit
A Q of 35 at 1 MHz tells you this inductor has reasonable efficiency in narrowband tuned circuits around that frequency — think LC filters or impedance matching in the low-MHz range. The self-resonant frequency of 15 MHz is the point where the parasitic capacitance across the winding cancels the inductance; above this the part looks capacitive. For a 22 µH value, a 15 MHz SRF is typical for an unshielded wirewound construction.
Package and temperature grade — board-fit and environment
No shielding means the magnetic field radiates; keep sensitive traces or other magnetics at least a few mm away to avoid coupling.