By Jim Holbrook, General Manager, Networking and Communications Timing at IDT

One of the most significant technological changes that has occurred in the past decade has been the shift from parallel to serial busses for high-speed system I/O and also for chip-to-chip interconnect. Examples of this trend are:

•PCI Express for PCs, servers and increasingly in networking and communications platforms

•Serial RapidIO for wireless base stations

•Infiniband and Fibre Channel for data centers

•VITA 46.X for industrial/military

Why the transition to serial busses? They offer two key advantages relative to parallel busses:

1) Much higher MByte/pin throughput

2) Easier scalability — just add additional, independent serial lanes when higher throughput is required.

Every day, high-speed serial interfaces place new demands on reference clock performance. Some of these demands include higher overall performance and more sophisticated methods to measure/verify performance, for example, frequency domain-based measurements, such as phase noise and integrated phase jitter.

Two other technologies are pushing the performance requirements of reference clocks to very high levels, even higher than the aforementioned serial busses: 100 Gigabit Ethernet and analog-to-digital converters (ADCs) on radio frequency cards, particularly in 4G base stations using the LTE standard. These types of applications require phase jitter performance as low as 0.2 picoseconds rms, which is very stringent but necessary to provide low bit error rate (BER), error vector magnitude (EVM) and low aperture error for ADCs.

These two macro-trends for timing solutions — much higher performance requirements and also more sophisticated measurement techniques — present challenges but also great opportunities. The drive for higher performance to support higher bus bandwidth greatly decreases the likelihood of integrating the clock PLL into an ASIC, thus ensuring a long-term market for reference clock chips.

This also allows clock vendors to clearly differentiate, because exceeding minimum phase noise/phase jitter specifications translates directly into better system performance via lower bit error rates.

New standards and higher-speed busses present challenges, but also great opportunities for sophisticated, responsive and system-focused clock vendors. The performance treadmill ensures long-term viability of reference clocks (militates against integration into an ASIC) and also provides great opportunities for clear performance and feature differentiation.

Kay Annamalai, Director, Timing Products, Pericom

Recent technological changes in ultra mobility, storage, networking and broadband access segments have been rapid, forcing timing solutions to gain high-speed capabilities in smaller footprints, including small size crystals and precise oscillators, low-jitter, high-frequency differential oscillators and integrated clock generator and buffers. These changes are positive, because they challenge us to create solutions addressing signal integrity and system stability, areas of expertise for Pericom, and these solutions address changes across market segments.

Smart phone wireless connectivity requires very precise and low phase noise, very low harmonics and high Power Supply Rejection Ratio (PSRR) timing solutions to meet the stringent RF compliance requirements of wireless standards like 802.11n. These are met by using a higher cost Temperature Compensated Crystal Oscillator (TCXO), or a lower-cost, high-performance Application Specific Standard Product crystal oscillator (ASSP XO) with clipped sine-wave outputs such as the UJ series from Pericom.

Rapid growth of System-In- Package (SIP) solutions with applications like wireless modules, smart cards for mobile payments as well as use of SD cards in cell phones, digital cameras, digital video recorders require small size crystals and oscillators. Pericom’s US series offers very small size crystals with dimensions as low as 1.6mm x 1.2mm with 0.35mm maximum height.

Storage markets require faster connectivity such as 6Gbps SAS2 for hard disk drives, host bus adapters and storage arrays. SAS2 solutions need very low phase jitter, high PSRR oscillators to ensure integrity of vast amounts of critical data. Pericom’s FD series ASSP XO perform best in these applications.

Increased adoption of cloud computing drives rapid adoption of higher speed network connectivity such as 10Gbps Ethernet (10GbE) interface. Data center networking requires high port count switches with 10GbE interfaces that are either copper or fiber. 10GbE physical layer interfaces need standard high speed reference clocks with low jitter and high PSRR. Pericom’s cost-effective LC PLL-based clocking solutions integrate clock generation and clock buffer functions, eliminating the need for multiple discrete timing solutions.

Pericom is well positioned for this shift to higher protocol speeds, lower jitter, and applications-specific solutions with its industry unique ownership of both quartz-and-silicon-based timing technologies.

James Wilson, Marketing Director for Timing Products, Silicon Labs

Until recently, timing was an unheralded, sleepy corner of the electronics industry. Most clock generation was done using crystal oscillators (XOs). In more complex systems, fanout buffers and clock generators provided additional clock synthesis. Hardware designers selected timing components near the end of the development process, long after the processor, system interface and other mission-critical components were selected. The pace of technological change was relatively modest given these market dynamics.

Then, in dramatic fashion, a convergence of two market trends made a huge and lasting impact on the timing industry. First, to keep pace with surging demand for Internet access and wireless broadband, data transmission rates for wired and wireless networks increased substantially, creating the need for more frequency flexible, low-jitter, high-frequency clocks. Careful clock architecture design became critical since clock jitter and phase noise directly impact signal-to-noise and bit error rate in performance-sensitive applications.

Second, the transition from analog to digital technology in TVs, cameras and other consumer applications led to rapid miniaturization, putting intense pressure on manufacturers to reduce size and cost through higher integration. For timing, this meant developing solutions that could replace multiple quartz-based components with a single IC.

These trends turned the timing industry into a hotbed of innovation and led to the invention of three breakthrough technologies that will irrevocably change the competitive landscape. First, clock IC solutions are now available that provide similar jitter performance as VCXO-based PLLs, making it possible for networking, wireless infrastructure and other applications requiring synchronization to migrate to IC-based solutions to minimize cost, simplify multi-rate clock synthesis and increase performance through improved noise immunity. Second, flexible clock generators are now available that enable the replacement of multiple XOs with a single device, simplifying design while minimizing size and power.

Third, MEMS and silicon oscillators are available to replace crystal oscillators while offering more reliable startup and operation, improved aging, higher resistance to shock and vibration, and significantly shorter lead times. These three technological breakthroughs are making a long-lasting, positive impact on the electronics industry by providing hardware designers more highly integrated solutions while improving performance and minimizing cost.

Piyush Sevalia, VP, Marketing, SiTime Corporation

The Internet boom of the last decade has spawned large innovations in all electronics. Correspondingly, electronic component suppliers have to provide products that have enhanced features, performance and integration with lower power, size and cost. In addition, because electronics is designed and manufactured worldwide, short lead times and easy availability are absolutely necessary.

Modern electronics relies on clocks as the heartbeat of the system. Therefore, timing components are ubiquitous in electronics, and the industry is very large, comprising over $5 Billion in annual revenues.

In the past, timing components have used quartz-based resonators married with analog circuits. The process of manufacturing quartz resonators is highly mechanical, uses grinding, plating and polishing extensively, and entails a unique and captive infrastructure. This results in 12-18 week lead times and extremely complex supply chains. Additionally, unlike semiconductors, the innovation and intelligence is in the manufacturing processes rather than in circuits. Semiconductor vendors are driving a paradigm shift in the timing market to overcome these shortcomings and service the electronics industry more effectively.

Silicon MEMS (Micro Electro Mechanical Systems) is one such technology that is rapidly being adopted for the timing market. MEMS components have been extensively used in automobile airbags and traction control systems to save hundreds of thousands of lives. In the timing market, SiTime has successfully replaced quartz with higher performance, more robust and reliable Silicon MEMS technology, and has shipped over 20 million units to the world’s largest electronics companies. SiTime’s products are 100% drop-in replacements for quartz and offer additional benefits of enhanced features and performance, 3-5 week lead times, worldwide availability and smaller size and lower power.

For example, SiTime offers Spread Spectrum Oscillators that replace quartz oscillators without any board modifications. By using these devices, the system vendor can pass environmental testing without expensive additional components or costly re-designs. On the performance front, SiTime’s high-frequency Differential Oscillators uniquely offer 10 PPM stability, which enhances timing margin in systems, resulting in better reliability.

The rapid technological changes of the past decade have had a positive impact on the timing solutions market. Semiconductor vendors are offering higher performance, more cost-effective solutions that are easily available and meet the requirements of the electronics industry.