April 2012

Keeping the Right Perspective on Timing
By E.L. Fox, Jr., President, Fox Electronics

Discussions about technology have the power to clarify or the power to confuse, depending on the perspective they take. And when you overlay business desires for smaller, more powerful, more economical, and more energy-efficient components, it becomes even easier to overlook the underlying physics behind technology options.

It seems that we are experiencing a bit of that confusion in the timing device market right now, based on selective comparisons between oscillators using quartz as a reference source and MEMS (micro-electro-mechanical systems) technologies using silicon.

There is no doubt that the concept of silicon-reference MEMS technology is attractive to electronic designers who would love to integrate their total timing solution into a compact, low-power, commercially viable, monolithic solution.

But in all the excitement about the current iterations of silicon-MEMS timing technology, we have lost sight of the real performance and business advantages that configurable quartz oscillators are delivering in demanding applications.

To be sure, both materials – quartz and silicon – have their own unique properties in terms of physical performance as well as production convenience or economy. But the high Q-factor of quartz (defined as the resonance frequency divided by the resonance width) continues to offer excellent stability as a reference source – the initial influence on the quality output of an associated timing device.

Granted, Q-factor is just the starting point, and only part of the total equation. How specific quartz-based or silicon-based devices are designed and manufactured also play an important role in frequency range, stability, noise, jitter, cost and delivery time of the finished component solution.

In that respect, both silicon MEMS devices and configurable quartz oscillators use compensating electronic circuitry to refine the output signal of their respective reference devices to the specific needs of the application.

But a key factor is that – even within products using the same reference source – not all timing devices are created equal. Therefore, inferring the performance of all quartz-based devices by the characteristics of one specific design is no more relevant than judging the quality all silicon-MEMS devices by the performance of one implementation.

Making broad claims that quartz oscillators have shortcomings in terms of limited frequency, limited pull-range options, inherent production problems, and long lead times ignores proven quartz technology breakthroughs, such as configurable oscillators that deliver clean, accurate timing signals at custom frequencies up to extremely high ranges.

Today’s high-quality configurable oscillators deliver reliable performance across a full range of target frequencies from 0.750 MHz all the way up to 1.35 GHz. They also offer stabilities as tight as +/-20 ppm, reduce jitter to the range of 0.3 pS to 0.5 pS, satisfy voltage requirements down to 1.8 V, and offer package sizes down to 3.2 x 2.5 mm – at costs equal to or better than conventional quartz oscillator designs.

Best of all, because the unique modular design of these configurable oscillators uses stocked components and customizable configuring, it enables users to receive custom test samples in a matter of days and full production runs in less than two weeks.

Furthermore, that complete track record of performance and efficiency can be affirmed by scores of satisfied electronics manufacturers using configurable quartz oscillators for products ranging from consumer electronics, to telecom, to stability-critical 10 G Ethernet applications.

There is nothing wrong with promoting the promise of new technology. We have certainly experienced some amazing transformations in our lifetime, from discrete transistors to ultra-powerful microprocessors.

We should embrace the advance of proven technical progress, in any form, but also keep a focus on those innovations that are delivering proven performance, while newer technologies emerge. It is what our customers expect and deserve. To paraphrase Mark Twain, claims of quartz’s demise are greatly exaggerated. In the meantime, let us all keep a proper perspective on timing.

Fox Electronics
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