Looking for a high-current solution with easy integration and noise suppression? Find out how this new SMD choke series could improve your designs.

TDK Corporation has introduced the EPCOS SurfIND series, a new line of current-compensated ring core double chokes designed for high currents and surface mounting. The series provides an SMD solution for customers who require high-current common-mode chokes but prefer reflow soldering, such as those used in telecom equipment and industrial drives. Main applications include suppressing common-mode interferences, switch mode power conversion, and frequency-variable drives.
The company claims that the chokes filter common-mode noise for rated currents from 24 A to 36 A at +70 °C, with the potential for higher currents when additional cooling is applied. The top side of the component allows direct heat sink attachment for efficient thermal management.
Designed for applications up to 250 V (AC), the series includes seven variants with nominal inductance values between 120 µH and 820 µH. With stray inductance up to 1% of the nominal value, these chokes also reduce differential-mode noise. All models comply with IEC/EN 60938-2 standards and share a 40 x 38 mm (L x W) footprint, with heights of 20.7 mm for A types and 22.3 mm for B types. Typical resistance ranges from 0.78 mΩ to 2.21 mΩ, and inductance remains within 10% of the nominal value at rated current with DC magnetic bias at +20 °C.
Some of the key features of the EPCOS SurfIND series include:
- High-rated currents at high temperature
- Low profile with defined height dimension
- Self-leaded SMD terminals suitable for reflow soldering
- Ferrite core with epoxy coating and plastic base plate (UL 94 V-0)
- Approx. 0.6 to 1% stray inductance for differential-mode noise suppression
Each SurfIND choke is mounted on a plastic baseplate with a ferrite core coated in epoxy for insulation. Both materials meet UL 94 V0 standards. The design eliminates the need for adhesives, and self-leading SMD leads simplify reflow soldering to PCBs.