Frequency control product manufacturers face increasing pressure

As the miniaturisation trend continues, designers also have to keep up with increasing consumer demands for a smaller and lighter footprint, without compromising performance. A glance at the latest trends confirms that frequency control product manufacturers are under more pressure than ever to produce improved timing solutions with greater performance, more integration and faster response times. Making its bid for a chunk of the $5billion timing market is Californian analogue semiconductor firm SiTime. The company has claimed many industry firsts and recently announced the first ±0.5ppm silicon MEMS tcxos, capable of achieving frequencies up to 220MHz and operating from a 1.8V supply. According to Piyush Sevalia, SiTime's vice president of marketing, the company was also the first to offer vctcxos, as well as vcxos with up to ±1600ppm frequency pullability. The company's silicon based SiT3808 and SiT3809 vcxos, released in May this year, are said to achieve 'groundbreaking' results, including better analogue performance and fine tuning in the system. "SiTime has used its silicon MEMS technology and programmable analogue expertise to accelerate innovation in the timing components industry," he said. "Through this we have been able to achieve 10 times more robustness and reliability compared to quartz devices. Unlike the quartz industry, SiTime also offers web enabled software development tools that allow engineers to customise a device exactly for their application, request samples, and receive them within a week. This flexibility, along with three to five week lead times, is accelerating the electronics industry's move to MEMS based timing." Furthermore, Sevalia believes the move to silicon technology has enabled devices with better features, higher performance, stronger reliability and lower cost trajectory than quartz crystal suppliers. "We believe that this helps solve engineer's problems and helps them get their products to market more quickly and cost effectively," he noted. "With the advent of silicon MEMS technology, it is also easier to get smaller and thinner devices. This is because they are manufactured in silicon, which takes advantage of Moore's Law and smaller geometries. The quartz industry cannot take advantage of this, so quartz devices are not shrinking as fast." Steve Wilson, technical director at Scottish oscillator manufacturer RFX, has also witnessed a growing shift towards MEMS based products in recent years. "The low cost market is now starting to become dominated by chip scale solutions, such as MEMS. Traditional packaging of low cost crystals in old style packages such as the HC-49/U case and its low profile equivalents has all but ceased and smd designs now satisfy most of the market. Metal cased clock oscillators are also nearly extinct, with miniature smd devices used in all new designs. The rapid development of MEMS oscillators is also the choice of all new volume applications where a mere clock facility is required and the oscillator is fabricated into the silicon." Reports indicate that the silicon MEMS timing market will grow at a compound annual growth rate of 66.4% per year between now and 2016. However, Andy Treble, Euroquartz' sales and marketing manager, believes MEMS oscillators hold no competition over quartz crystals. "MEMS technology has appeared in recent years, but these oscillators seem to have niche applications, rather than a panacea for the use of quartz crystals," he said. Wilson also notes that such low specification MEMS devices cannot provide the very high frequencies and accuracy of the larger high specification devices. "They do, however, have the advantage of very small size and their minimum weight gives good shock and vibration survival," he said. So what are designers look for when choosing timing solutions? "Frequency control devices are the heartbeat of electronics," stated Sevalia. "Designers are now looking for features to solve their problems, as well as a good price/performance ratio and excellent reliability." What is also clear, as both Treble and Wilson note, is that there is now more choice available than ever before. "The frequency control industry had been stuck in its traditional pattern of mechanical, labour intensive production methods for decades," stated Wilson. "New demands on the accuracy of devices and the lowering of costs for basic clocks have finally changed the industry. It is now becoming dominated by semiconductor industry production methods, with on the one hand very low cost and on the other hand increasing demands for integration and improvements in specifications. These include reliability, accuracy and shock and vibration capability." Treble concurred: "Designers are now looking for devices with long term stability, very low phase noise, higher frequencies and the ability to withstand increased levels of shock and vibration. In response, tighter manufacturing processes are being implemented and companies are making investments in clean room facilities for quartz crystals and higher frequency test systems. They are also looking at the integration of control facilities within precision oscillators." Overcoming challenges In terms of footprint, Sevalia says technologies such as chip scale packaging are helping to reduce overall dimensions. "In the silicon industry, there is a huge infrastructure for extremely small packages," he said. "Quartz crystal manufacturers have to work with their ceramic package suppliers to develop and bring out newer packages, which takes some time. In addition, the biggest roadblock is the ability to cut and grind the crystal to a very small size. That is not easy, and in some cases, such as 32.768kHz real time clock resonators, it is a real problem for mobile phone manufacturers." In terms of the future, Wilson sees the market splitting between traditional, high specification products and low cost chip scale products. He believes the industry will soon see the introduction of atomic scale clocks and oscillators with their own on board controls and integration with custom designs. He also asserts that more and more functionality will be built into future products to reduce the component count on pcbs and assist in the miniaturisation process. Sevalia, on the other hand, is confident that silicon MEMS technology will dominate the industry in the years to come. "Because of the features and benefits that we offer, we see an acceleration in usage of silicon MEMS timing devices by the electronics industry," he noted. "We have shipped more than 50million units to date in the four years that we have been shipping these products and every year we have shipped more than all previous years combined. We believe this trend will continue for many more years." As well as increased functionality, Treble anticipates the rapid migration to very high performance networking and telecom applications. "In short, we expect more integration," he concluded. "The big goal for manufacturers is to try and reduce things to a single chip, but, as frequency requirements are so varied and complex, this remains to be seen."