120 µH wirewound for filter and bias-T applications
The Murata LQH43MN121K03L is a drum-core wirewound inductor in the LQH43 series, offering 120 µH inductance with ±10% tolerance in an 1812 (4532 Metric) surface-mount package. Rated for 150 mA continuous current with a maximum DC resistance of 3 Ohm, it is suited for power supply filtering, DC-DC converter output chokes, and bias-T circuits where the inductance value and current rating align with the rail budget.
Self-resonant frequency and Q factor — where the inductor behaves
The self-resonant frequency (SRF) is 6.2 MHz, meaning the inductor's impedance peaks and its inductive behavior transitions to capacitive above that frequency — keep the operating frequency well below 6.2 MHz to avoid unexpected filtering roll-off or resonance. Q factor is specified at 40 measured at 796 kHz, indicating moderate energy efficiency at that test frequency; the actual Q varies with frequency and is highest near the SRF, but the 796 kHz point gives a reference for filter insertion loss in the low-MHz range. The unshielded drum-core construction means the magnetic field extends outside the component — adjacent traces or other inductors on the same board may couple, so maintain spacing or orient orthogonal to sensitive circuits.
Temperature range and board-fit for the 1812 footprint
Operating temperature range is -40°C to +85°C, covering industrial and commercial environments but not extended automotive under-hood or high-temperature power supply sections where ambient exceeds 85°C.