AEC-Q200 — what the grade certifies for the BOM
The LPS4018-683MRC: Rated AEC-Q200, the passive-component automotive stress qualification. This covers 1000-hour accelerated life at rated current and 125°C, thermal shock between -40°C and 125°C, mechanical shock and vibration per the AEC-Q200 test plan. The inductor is qualified for under-hood and cabin deployment without additional derating beyond the datasheet limits.
68 µH at 400 mA — the saturation margin for a DC-DC choke
Inductance is 68 µH at 100 kHz test frequency, ±20% tolerance. Rated current is 400 mA; saturation current is 410 mA. The 10 mA gap between rated and saturation means the inductor operates below the knee of the BH curve at full rated load — inductance holds within 10% of nominal up to the saturation point. For a buck converter switching at 500 kHz to 2 MHz, the 13 MHz self-resonant frequency leaves margin above the switching harmonics before the impedance turns capacitive. DC resistance is 950 mOhm max. At 400 mA the conduction loss is I²R = 152 mW — within the thermal budget of the 3.90 mm x 3.90 mm footprint without forced airflow. The shielded ferrite core contains the magnetic field, reducing EMI coupling to adjacent traces or a nearby RF stage on the same board.
Footprint and stack-up — 3.90 mm square, 1.80 mm tall
Nonstandard surface-mount package, 3.90 mm x 3.90 mm land pattern, 1.80 mm seated height. The low profile suits mezzanine card or module assemblies where the board-to-board clearance is under 2.5 mm. The ferrite core and shielded construction mean no keep-out zone for adjacent copper planes — the inductor can sit under a shield can or near a board edge without coupling into the chassis.