Available in either DO-35 or mini-MELF package, the 1N6263 of Excel , mainland China, features inverse voltage of 60V and series forward current of 15mA

The small-signal diodes segment is expected to represent about a third of the worldwide diode market share, which is forecast to reach $2.4 billion in 2007. According to the Worldwide Semiconductor Trade Statistics, a large percentage of the global supply of small-signal diodes will come from Greater China, one of the largest production bases for diodes and diode modules.

The production volume of mainland China-made small-signal diodes is likely to scale up by 20 percent this year, representing a significant share of the region's total diode and diode module output. Some 30 billion units of diodes and diode modules were produced last year; this figure is expected to grow to 36 billion units this year. Taiwan, also a key supplier base, focuses production mostly on high-end small-signal diodes suitable for portable electronic devices.

The strong market performance of surface-mount small-signal diodes in smaller footprints is expected to continue as consumer electronics and communications devices become increasingly more compact. PanJit Int. Inc. from Taiwan manufactures surface-mount small-signal diodes, and small-signal zener, Schottky and switching diodes. Its small-signal switching diodes feature ratings of 0.2W to 0.5W while small-signal Schottky diodes have ratings of 0.2A to 1A. The switching diodes come in packages of DO-41 and DO-35, while surface-mount mini-MELF come in SOD-523, SOT-363, SOD-323, SOT-323 and SOT-23 packages. The company also offers small-signal Schottky diodes in SOD-123, SOT-323, SOD-323,DO-35 and mini-MELF package.

PanJit allocates 3 percent of its annual sales to R&D, which is conducted in Taiwan and in Arizona in the United States. Its R&D team of 50 can turn out 15 new models annually. The company plans to expand its product line to QFN small-signal switching diodes and small-signal Schottky diodes.

Won-Top Electronics Co. Ltd produces surface-mount zener diodes, small-signal Schottky diodes and ultrafast rectifiers. Its small-signal Schottky diodes feature ratings of 0.2W to 0.5W. Won-Top currently has a 15-person R&D department, which releases two to three new products monthly. The company's popular models include small-signal Schottky diodes in SOD-323 and SOT-323 packaging.

Taipei-based Daco Semiconductor Co. Ltd offers small-signal diodes with ratings of 30mA to 350mA with packaging of SOD-80, SOT-23, SOD-123, SOD-323, MELF, DO-34 and DO-35. Daco regularly deve-lops new technologies and owns more than 20 patents for its products. The company has 18 R&D workers who develop over 100 diode models annually.

To catch up with their foreign counterparts, mainland China makers allocate an average of 3 percent of annual sales to R&D. Makers continue to extend product applications to more portable consumer and communications devices. Surface-mount small-signal diodes are also mainstream for these makers.

Excel (Suzhou) Semiconductor Co. Ltd focuses its R&D on midrange and high-end small-signal diodes used in communications equipment, electronic instruments, home appliances and cars. The company's BAV103 series of small-signal diodes come in SOD 80/mini-MELF packaging and feature high reliability.

Wuxi Xuyang Electronic Co. Ltd recently unveiled five new models of miniature small-signal diodes for communications applications.

ON Semiconductor from Hong Kong likewise continues to focus on miniaturized discrete packaging. The company's most compact surface-mount package for small-signal diodes is the SOD-923, with dimensions of 1x0.6x0.4mm. Next year, ON Semiconductor aims to develop more compact small-signal diodes with better silicon performance.
Output growth stays at 20 percent
Export markets to broaden

Greater China's total output for small-signal diodes has been growing by 20 percent in the past few years, and makers expect the trend to carry over to this year and the next. Industry growth drivers will be ESD protection applications, specifically portable 3C devices.

At present, about 30 companies on the mainland are engaged in the production of small-signal diodes. Most of these companies are privately owned, small- or medium-scale enterprises. At least 10 percent of the companies are foreign-owned. For the next few years, makers will emphasize improving their manufacturing technologies and enhancing manufacturing capability. At present, most makers are running at about 70 percent of their utilization.

Excel, which has a monthly capacity of 190 million units, plans to construct a new factory in Suzhou with an area of 10,000sqm.

Having raised its capacity by 50 percent last year, Wuxi Xuyang will retain its capacity level of 30 million units per month. The company has already adopted lead-free tin plating techniques.

ON Semiconductor's Hong Kong sales office deals with its business in Asia Pacific. The company mostly manufactures small-signal diodes for applications in LCD TVs, mobile phones and digital still cameras. Its factories are located in Arizona and Oregon in the United States; Roznov, Czech Republic; Piestany, Slovakia; Leshan, mainland China; Aizu, Japan; Seremban, Malaysia; and Carmona, in the Philippines.

PanJit is one of the larger suppliers of small-signal diodes in Greater China. It has a monthly capacity of 700 million units for glass-passivated small-signal diodes and 350 million units for molding compound small-signal diodes. Vice President Golden Chuang says the sectors that will drive demand are portable electronics, MP3 players, notebook PCs and e-books. The company's main production center for small-signal diodes and wafers is in Kaohsiung. Expansions on its Suzhou and Wuxi plants have recently been completed.

For Won-Top, orders will more likely come from makers of mobile phones, digital cameras and PCs, says Sales Manager Eric Tsai. Its Kaohsiung facility currently focuses on manufacturing high-end rectifiers and power diodes, while the Shandong plant focuses on low-end power diodes.

Daco also has two factories in mainland China, which produce small-signal diodes and general rectifiers. The Taiwan plant produces high-power modules and MELF series. The company will ramp up its capacity for small-signal diodes with ratings of 15A to 600A.

The majority of the mainland China makers export their products to Europe, North America and Southeast Asia, but a lot of makers plan to tap into the Middle East and South Asia. On average, about half of the total small-signal diode output is exported. To facilitate the increase in export volume, some makers will open new offshore offices. Makers are likewise complying with the RoHS and WEEE directives to increase their share in the global market. Overall export from China is likely to undergo a growth of 15 percent to 20 percent next year.

Suzhou Good-ark Electronics Co. Ltd exports 95 percent of its products, with OEM sales accounting for 40 percent of total sales.

Wuxi Xuyang realized export values of up to $1.5 million last year, up 50 percent from $1 million in 2004.

PanJit's worldwide sales account for about 5 percent of its overall sales, with major export markets including the United States and Europe. The company projects a 20 percent rise in exports in 2007. It participates in trade shows in Munich and Taipei to promote new products. Its sales mostly come from its own-brand products, which account for 85 percent, while OEM sales represent 15 percent.

Daco forecasts a 10 percent increase in overall shipments this year. Its shipment destinations are the United States, which absorb 20 percent of exports; Europe, 40 percent; and Asia, 30 percent.

For Won-Top, exports are expected to double by end-2006, most of which will come from the United States and South Korea. Other markets include Europe and the mainland.

Makers also give priority to QC to attract more international customers. PanJit has obtained ISO 9001 and ISO 14000 certifications. ON semiconductor has ISO 9001:2000 certification, and its products have TS 16949 approval, mostly for automotive small-signal diodes.

Won-Top has ISO 9001, ISO 14000 and QS 9000 certifications, while Daco has ISO 9001, ISO 9002 and QS 9000 certification.

Daco's products are UL-approved.