Signal line suppression in a 0402 footprint
The Murata BLM15BB121SN1D is a single-line ferrite bead from the EMIFIL® BLM15 series, designed to suppress high-frequency noise on signal lines. It delivers 120 Ohms of impedance at 100 MHz, a common reference point for conducted emission compliance in the 30-100 MHz band, where many switching regulators and digital clocks radiate. Rated for 300 mA continuous current with a maximum DC resistance of 550 mOhm, this bead adds a voltage drop of roughly 165 mV at full load — a figure to budget in low-voltage supply rails where every millivolt matters for load regulation.
Listed as Active in production, the BLM15BB121SN1D carries no lifecycle risk for ongoing BOM continuity.