EMI Suppression Solutions: Fair-Rite Ferrite Cores and Chips

Description

Application Scenarios

In a variable frequency drive (VFD) powering a factory motor, high-frequency switching noise generated by the drive’s insulated-gate bipolar transistors (IGBTs) can travel back along the power cables. This electrical noise, if unchecked, can radiate and couple into nearby sensitive equipment like sensor wiring or communication lines, causing erratic readings, data corruption, or even malfunctions. A Fair-Rite ferrite clamp-on core​ is a simple yet highly effective solution. Installed around the motor power cables at the drive output, this core acts as a high-frequency choke. It presents a high impedance to the unwanted high-frequency noise currents, absorbing their energy as heat and preventing them from propagating. This straightforward application of a Fair-Rite core​ directly solves the critical pain point of electromagnetic pollution, protecting sensitive electronics, ensuring reliable system operation, and helping machinery meet stringent EMC regulations.

Parameter Overview (Fair-Rite Product Families)

Fair-Rite offers thousands of parts. Key parameters are defined by material, size, and impedance.

Technical Principles and Innovative Values

Innovation Point 1: Proprietary Ferrite Material Science.​ Fair-Rite’s core innovation lies in its extensive library of proprietary ferrite material “mixes.” Each mix (e.g., 43. 61. 75) is engineered with a specific complex permeability profile, optimizing it for peak performance within a targeted frequency band. This allows designers to select a component that offers high impedance (and thus high attenuation) at the precise noise frequency troubling their circuit, whether it’s in the kHz range from switch-mode power supplies or the GHz range from digital clocks, while having minimal effect on the desired lower-frequency signal or power.

Innovation Point 2: Broad Product Ecosystem for Every Application.​ Fair-Rite provides an unparalleled range of form factors, creating a solution for virtually every noise challenge. This includes: Surface Mount Chip Beads​ for high-density PCBs, Toroidal Cores​ for winding custom inductors or filters, Cable Cores (Clamp-On/Snap-On)​ for retrofitting cables without cutting, Multi-Hole Cores​ for filtering multiple wires simultaneously, and Rods/Plates​ for specialized designs. This comprehensive portfolio allows engineers to address EMI at the source (on the board), along the path (on the cable), or at the receptor.

Innovation Point 3: Enabling Miniaturization and Compliance.​ As electronics have shrunk and speeds have increased, EMI challenges have grown. Fair-Rite’s miniaturized chip beads, some smaller than a grain of sand, provide critical noise suppression without consuming significant board space. Their components are fundamental in helping products meet global EMC regulations (FCC, CE, CISPR). By providing predictable, characterized performance data, Fair-Rite components allow designers to mitigate EMI proactively during the design phase, reducing the costly and time-consuming board spins often required to fix EMI problems during compliance testing.

Application Cases and Industry Value

Case 1: Data Integrity in Industrial Ethernet Networks.​ An automation system integrator was experiencing intermittent communication failures on a factory floor Ethernet network linking PLCs and HMIs. The issue was traced to EMI from nearby motor drives coupling onto the unshielded twisted pair (UTP) Ethernet cables. By installing Fair-Rite snap-on ferrite cores​ (using a high-frequency mix like #31 or #43) at both ends of the Ethernet cables, the high-frequency common-mode noise was effectively suppressed. This low-cost, non-intrusive fix eliminated the data corruption, restored network reliability, and prevented a costly re-cabling project with shielded cables. The plant engineer valued the simple, robust solution that required no system redesign.

Case 2: Filtering in Switch-Mode Power Supply (SMPS) Design.​ A designer of a compact 5V/10A DC-DC converter was failing radiated emissions tests due to noise at the switching frequency (500kHz) and its harmonics. By strategically placing a Fair-Rite toroidal core​ of Mix 52 (optimized for 1MHz-10MHz) as a common-mode choke at the input stage and using Fair-Rite chip beads​ of Mix 43 on the output power rails, the noise was attenuated by over 15dB. This brought the power supply into full compliance with CISPR 32 Class B limits. The ability to select materials targeted at specific noise frequencies allowed for a more optimized and cost-effective filter design than generic solutions, speeding time-to-market for the end product.

Related Product Combination Solutions

Engineers often combine Fair-Rite components for comprehensive filtering.

Chip Beads (e.g., 0443167251 – 600Ω @ 100MHz):​ Placed on individual PCB power or signal lines to filter noise at the IC pin level.

Common Mode Choke Cores (e.g., Toroids of Mix 31/43):​ Wound with multiple wires to filter common-mode noise on differential pairs (USB, Ethernet, motor leads).

Cable Cores (e.g., Snap-On 0443164181):​ Placed on external cables (power, data, video) to prevent noise from radiating from or coupling onto the cable.

Surface Mount Multi-Layer Chip Beads:​ Smaller, high-frequency beads for dense digital circuits (e.g., near clock generators, memory buses).

EMI Suppression Sheets:​ Flexible ferrite sheets used for gasketing or lining enclosures to absorb radiated EMI.

Fair-Rite Kits:​ Assortment kits containing a variety of core sizes and materials, invaluable for prototyping and testing during the design phase.

Selection, Application, and Support

Selecting the correct Fair-Rite​ component requires analysis: identifying the noise frequency, determining the impedance needed, checking the current rating, and choosing the form factor. Application is straightforward: chip beads are soldered onto PCBs; cable cores are snapped onto cables, ideally as close to the noise source or victim as possible. For toroids, wires are wound through the center; the number of turns increases impedance. Proper placement is key—a bead placed after a long, unfiltered PCB trace may be ineffective.

While the components themselves require no maintenance, system-level EMI troubleshooting involves using spectrum analyzers and near-field probes to identify noise sources and verify filter effectiveness. A failed ferrite (e.g., cracked from mechanical stress) typically loses its filtering properties and should be replaced.

We provide comprehensive support for your EMI challenges. Our services range from helping you identify the correct Fair-Rite material mix and part number​ for your specific noise problem, to supplying samples from our broad inventory, to providing application notes and technical data sheets. We understand that EMI compliance is critical to your product’s success.

Solve your EMI/EMC challenges with the industry leader. Contact us for technical assistance in selecting the optimal Fair-Rite ferrite component for your design.