What 220 Ohms at 100 MHz means for your noise filter
The BLM15EG221SH1D is a single-line ferrite bead from Murata's BLM15EG series, delivering 220 Ohms of impedance at 100 MHz — this is the frequency where most conducted EMI from switching regulators and digital clocks peaks. Below 10 MHz the bead acts as a low-resistance conductor (280 mOhm DCR max); above 100 MHz the impedance rolls off as the parasitic capacitance dominates.
Current rating and DCR: the thermal budget trade-off
Rated for 700 mA continuous current, the 280 mOhm DCR means a voltage drop of 196 mV at full load and 137 mW of self-heating.
AEC-Q200 and the 0402 footprint: what the qualifications buy you
AEC-Q200 qualification means this bead passed the automotive-grade stress tests: vibration, mechanical shock, solder heat resistance, and 1000-hour high-temperature operating life at 125 °C. The 0402 (1005 metric) package — 1.00 mm × 0.55 mm with a 0.55 mm seated height — fits the tight clearances of a camera module, ADAS ECU, or infotainment board where board space is the constraint, not the current draw.
Active production and sourcing posture
No direct functional replacement exists within the BLM15EG series at this impedance and current rating — the 221 impedance code (220 Ohms) is specific to this variant.
