Ferrite chokes cut space for high-current designs

Steward's new CM1812x330R monolithic surface mount common mode chokes are designed for power and data line EMI filtering where high current, small size or high frequency performance is required.

Steward's new CM1812x330R monolithic surface mount common mode chokes are designed for power and data line EMI filtering where high current, small size or high frequency performance is required.

This new family of compact ferrite parts includes versions rated at 5 and 10A: all the family members feature very low DC resistance to minimise signal distortion, and low common mode impedance of at 100MHz.

The new series will find applications in a number of areas, including EMI suppression on the DC power traces on printed circuit boards (PCBs), especially in applications of greater than 3.0A.

High-speed I/O circuitry such as network and storage subsystems also need such common-mode EMI suppression, as do USB power lines, PCMCIA products, disk drives, and equipment intended for Bellcore Telecom applications.

The devices are smaller, lighter and less susceptible to vibration than older-style wire-wound chokes, making them ideal for use in harsh environments and portable equipment.

Available in lead-free, RoHS-compliant variants, the 5 and 10A rated devices exhibit DC resistance of 3 and 5mohm, respectively: at 100MHz the common mode impedance remains low - at 60 and 33ohm, respectively - before rising steeply to suppress unwanted signals in the gigahertz range.

There is no derating effect on the impedance values under bias or extremes of load current.

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