70 Ohm noise suppression at 100 MHz
The Murata BLM15AX700SN1D is a single-line ferrite bead from the EMIFIL BLM15 series, offering 70 Ohms impedance at 100 MHz. This impedance peak targets conducted EMI in the 30 MHz to 300 MHz range — the typical switching noise band for DC-DC converters, clock lines, and digital I/O. At 780 mA continuous current rating, the bead maintains its impedance without saturating the ferrite material; above this current the effective impedance drops as the core approaches magnetic saturation. The 0402 footprint (1.00 mm x 0.55 mm body, 0.55 mm max height) fits into dense PCB layouts where board space is at a premium, such as mobile devices, IoT modules, and compact power supplies.
The ceramic construction and nickel barrier termination handle thermal cycling without parametric drift — the impedance curve shifts less than 10% across the temperature range per Murata's typical characteristic.