AEC-Q200 qualified for under-hood power rails
The Murata DFE2MCAHR47MJ0L is a 470 nH shielded wirewound inductor from the DFE2M series, qualified to AEC-Q200 Grade 0 for operation from -40°C to +150°C. This temperature range covers the under-hood and transmission-bay thermal profile — an engine ECU or transmission control module that sees 125°C ambient still has 25°C of margin before the part derates. In a dense power supply layout, the shield prevents coupling into adjacent sense lines or feedback traces — a common failure mode when an unshielded drum core sits next to a 2 MHz switching node.
Current rating and DCR — the thermal budget decision
Rated 3.5 A continuous with a saturation current (Isat) of 3.6 A and a maximum DC resistance of 33 mOhm. The narrow 0.1 A gap between the rated current and the saturation floor means the inductor's core does not begin to lose inductance until the current exceeds the continuous rating — for a buck converter output stage, the peak-to-peak ripple current plus the DC load must stay under 3.5 A to keep the inductance within the ±20% tolerance band. At 3.5 A the I²R loss through the 33 mOhm DCR is 0.4 W. A two-layer board with a solid ground pour under the part handles the dissipation; a thin flex circuit may need a wider copper pour.