EMI filters are critical in Brushless DC (BLDC) motor systems, particularly within DC-DC converter switching modules, where high frequency switching noise can propagate throughout the system. Johanson’s lightweight SMD ceramic construction makes them ideal for space and weigh sensitive designs while maintaining high electrical performance.

Johanson multi-functional EMI filters provide an integrated solution to attenuate unwanted electromagnetic interference across a wide frequency range while allowing DC and desired signals to pass unaltered. Supporting both single-ended and differential configurations, these filters deliver effective attenuation from 100 KHz to 20 GHz, with suppression levels up to 60 dB — enabling designers to address both conducted and radiated emissions at the source. Ultra-low equivalent series inductance (ESL), combined with no DC voltage drop and no current limitation, ensures filtering performance without sacrificing system efficiency or reliability.

Furthermore, DC brushed motors are a primary source of EMI, generating broadband noise through commutation, brush arcing and fast switching currents. In mission-critical applications such as military, aerospace, defense and industrial electronics. This noise can compromise system stability, degrade signal integrity and lead to compliance failures. Ensuring predictable and robust EMI suppression is therefore essential.

By replacing up to seven discrete components and common mode chokes with a single EMI filter, designers reduce layout-dependent variability and minimize potential failure points associated with multiple solder joints. This integration improves repeatability and long-term compliance with stringent EMC standards.

Johanson Dielectrics
Camarillo, Calif.
www.johansondielectrics.com/contact/ask-a-question/