Miniaturization drives steady ascent of SMD coils

DIP types still dominate coil production but makers press on with the release of more SMDs to widen reach in this core passive component market.

Mainland China suppliers of coils keep the mature line up-to-date with miniaturization by progressively increasing the output share of SMD types while continuing to turn out traditional DIP kinds. This is to cater to diverse applications in the consumer electronics, computer, telecom, home appliances, industrial, military and defense fields, and emerging uses in automotive electronics and LED lighting. Based on projections, these markets will ensure about 10 percent annual sales growth locally in the near term, which is double the forecast for the global category. The first three sectors will still be the major demand drivers.

Anhui Shirui Electronic Technology Co. Ltd will allocate 40 percent of turnout for SMD kinds in coming months from about 30 percent at present. Goldenbamboo Electronics (ZH) Co. Ltd is aiming for a 10 percent boost for the variant to have a 30 percent portion by end-2017.

At present, units designed for surface mounting account for about 30 percent of domestic coil production.

For Hefei Mycoil Technology Co. Ltd and XP Power Electronics Co. Ltd, the yield shares of conventional DIP coils will remain respectively at 90 and 80 percent.

In addition to miniaturization, mainland coil manufacturers are pursuing trends for wider rated current and operating temperature ranges to meet various requirements. Shenzhen Yamaxi Electronics Co. Ltd has an edge-wound choke coil with 30 to 200A rated current. XP Power uses a sendust core in its differential-mode choke coil, which supports an operating temperature of -40 to 200 C.

To realize greater Q value, suppliers adopt insulated multistrand or single-wire winding method according to operating frequencies. They also use better dielectric materials such as high-frequency ceramic and PTFE for the bobbin.

Some 300 suppliers make up the line in the mainland, about 80 percent of which are locally owned. The rest of the pool includes major industry players such as TDK, Murata, Toko and Sumida, and a number of companies from Taiwan and Hong Kong.

The manufacturers gather mainly in the Pearl River and Yangtze River Delta regions. The key production hubs are in Guangdong, Jiangsu and Zhejiang provinces.

The mainland's coils account for nearly 30 percent of the global yield.