8.2 µH, 300 mA — the DC-DC filter inductor for automotive power rails
The Murata LQH32NH8R2J23L is a drum core wirewound inductor delivering 8.2 µH ±5% at a rated current of 300 mA. With a maximum DC resistance of 480 mOhm, the I²R loss at full rated current sits at roughly 43 mW — well within the 125 °C ambient ceiling for a 1210 footprint.
Frequency ceiling and Q — where it works and where it doesn't
The self-resonant frequency is 40 MHz, with a Q of 20 measured at 1 MHz. Below 40 MHz the component behaves as an inductor; above that the parasitic capacitance dominates and the impedance drops. This sets a practical upper switching-frequency limit around 10–15 MHz for a buck converter's inductor — beyond that the effective inductance collapses. Unshielded construction means the magnetic field radiates from the drum core. In a layout with sensitive analog or RF traces on the same layer, maintain a keep-out zone of at least one part width (3.2 mm) around the inductor to avoid coupled noise into the signal chain.
1210 footprint and PCB integration
The ferrite core material handles the DC bias without saturating up to the rated 300 mA — derate the current above 85 °C per the Murata application note for the LQH32 series.