Frequency source gets chipped

Frequency generation is one of the fundamental elements of electronics design. Whether building a simple garage door opener or a sophisticated space navigation system, a component is required in the design which generates high frequency timing signals to synchronise communications among ICs, PCBs, and complete systems.

Currently, the task of frequency generation is usually carried out by piezoelectric materials such as quartz crystals or ceramic resonators.

But the shrinking dimensions of many electronic products make the large, bulky packaging required for crystals unacceptable. And as multimedia applications drive up the amount of bandwidth required by consumer electronic devices, standard reference frequencies are increasing beyond the capabilities of low cost, fundamental mode crystals.

Now, through the use of RF-capable CMOS processes and a precision analog CMOS design, Sunnyvale, California-based Mobius Microsystems has built a frequency source monolithically in silicon eliminating all the limitations imposed by quartz frequency sources.

The foundation of the company's patented CMOS harmonic oscillator design is a harmonic (LC) resonator circuit which, unlike common LC resonators that have long been used in low jitter PLLs, is designed to maintain the accuracy of its frequency in an open-loop configuration.

'The CHO technology removes the size, frequency and reliability limitations of quartz all of which are significant bottlenecks in electronics design today,' said Ashok Dhawan, chief executive of Mobius Microsystems. 'We believe that a widely used and deeply entrenched product such as quartz will only be replaced by an even more ubiquitous, proven and successful technology such as standard CMOS.'

Mobius’ first announced product to use the CHO technology is the MM8511, a fully integrated spread spectrum clock generator IC. The device replaces a quartz crystal and a PLL timing IC, and offers a single chip solution that is available in a variety of output frequencies and spread spectrum profiles.