6.8 mH shielded drum core — what the ratings mean for your DC-DC filter
The Coilcraft LPS6235-685MRC is a 6.8 mH shielded drum-core inductor in the LPS6235 series, qualified to AEC-Q200 for automotive stress screening. The 90 mA continuous current rating is the DC bias level at which self-heating from the 21.4 Ohm DCR starts to shift the inductance — stay below it to keep the filter corner frequency where you designed it. The 57 mA saturation current (Isat) is the hard ceiling: above this the ferrite core saturates and inductance collapses to a fraction of the nominal value, turning your LC filter into a wire. For a buck converter running at 100 kHz, the peak inductor current during a load transient must stay under this number or the output ripple doubles and the control loop loses phase margin.
Package and board-fit — 2424 footprint
The shielded ferrite drum core keeps the magnetic field contained, so adjacent traces carrying 24 VDC or a 100 kHz switching node see minimal eddy-current coupling — no extra keep-out zone beyond the standard 0.5 mm pad-to-pad clearance for the 2424 land pattern. The ±20% tolerance on the 6.8 mH value is typical for ferrite-core power inductors — the inductance drops about 10% from the nominal at 90 mA bias, so the actual filter cutoff shifts by roughly one-third of an octave over the load range. The self-resonant frequency of 800 kHz sets the upper bound for the switching frequency: above 400 kHz the parasitic winding capacitance starts to resonate with the inductance, and the impedance curve flattens.