But makers are stepping up move to chip wirewound and multilayer types to match the miniaturization trend in consumer electronics.
Suppliers of inductors in China continue to improve and expand their selections to match requirements in traditional and burgeoning applications. Wirewound types currently dominate production, accounting for nearly 90 percent of aggregate yield. Makers focusing on this variety underscore the mature category’s reliability based on high inductance and Q value ratings.
Despite the emphasis on staple configurations, companies are increasing efforts to steer the industry toward chip versions in line with the miniaturization trend. Many are also enhancing frequency and integration capability while streamlining the component’s profile.
Suppliers are pursuing two types of SMD chip inductors: wirewound and multilayer. The adoption of low-temperature co-fired ceramic or LTCC technology will boost the manufacture of the latter.
Besides a low profile, the product boasts greater frequency and integration features. They have magnetic shielding and reduced DC resistance and inductance. The first ensures noninterference with other components on a PCB, making the inductors suitable for high-density board assemblies. The capability to allow smaller current to pass through, meanwhile, meets applications requiring elevated frequencies. By structure, the integrated body has enhanced reliability, heat resistance and solderability. The regular shape is also fit for automatic production.
In the multilayer SMD chip subcategory, LTCC involves the use of ferrite and conductor slurries to print, laminate and sinter alternately to form a closed magnetic circuit. It employs thick-film multilevel passivation, which together with the lamination process, enables supercompact sizes. In contrast, wirewound versions have structures made of copper wire coiled on the soft ferrite core and utilize resin for the outer encapsulation. These have a limited miniaturization range.
Despite the many advantages offered by LTCC and the resulting multilayer chip variant, the shift to this approach is undermined by the high technology barrier and investment. “One manufacturing line costs $3 million, and a maker has to own at least four to realize commercial production,” Shaanxi Shinhom Enterprise Co. Ltd general manager Jack Wang said. He added almost all facilities of local players are secondhand acquisitions from Japan and other countries.
An additional challenge is the inadequate domestic supply of raw materials. Enterprises such as Zhong Kai Electronic Co. Ltd cited this as reason why it has no plans to explore this type. To date, there are no more than 10 homegrown companies in the sector.
Zhong Kai, however, is optimistic conditions will improve in the next five years and more players will join. The category, after all, findswide use in mobile phones, PCs, wireless communication devices and high-speed portable digital electronics. The broadening application base will keep multilayer chip inductors on suppliers’ product development agenda in coming years.
Meanwhile, local makers are exploring available design alternatives to keep the line dynamic, especially as demand for wirewound SMD variants remains robust. Most units adopt I-shaped magnetic cores but there are H-designed ceramic options. The latter type’s inductance is low but the resonant frequency is greater at 5 or 6GHz, with the maximum reaching 12.5, appropriate for high-frequency applications. In addition, as the electrodes are prefabricated on the core, production is simple and further miniaturization possible.
This is pushing suppliers such as Shaanxi Shinhom to pursue the development of low-profile wirewound inductors this year. The maker is targeting a thickness of 1mm for SMD units to fit mobile devices. It will also continue to modify structures and shapes based on buyers’ requirements.
Zhong Kai, meanwhile, acquired three production lines to boost output of this type by 30 percent and meet rising demand in months ahead.
At present, China accounts for about 15 percent of the global supply of inductors. It is expected to churn out 27.5 billion units this year. This includes 12 billion chip, 10 billion fixed and 5 billion SMD variants, and the rest integrated into devices. Demand is anticipated to remain strong in future, driven by vibrant trends in various electronics, including the GPS, A/V and automotive sectors. more on wirewound configurations dominate inductor output…