Product Of The Year Story Behind the Story: Transitioning away from quartz-based oscillators

Product Of The Year Story Behind the Story: Transitioning away from quartz-based oscillators

On October 27, 2011, Integrated Device Technology introduced the world’s first ultra-low-power ±50-ppm CrystalFree CMOS oscillator. Generally, the frequency stability required for oscillators used in most datacom and telecom applications is ±50 ppm. Thus, in these applications, active crystal oscillators (XOs) are commonplace as opposed to lower-cost and lower-stability passive crystal resonators.

These existing XOs offer high stability, frequency, and performance, but at the cost of power and price. Using CrystalFree solid-state technology, 3LG was developed to meet the need for a low-cost and low-power ±50-ppm frequency reference.

The IDT team accepting the award

Overcoming challenges

3LG is the first oscillator to deliver ±50-ppm frequency stability with an all-CMOS, or solid-state LC-resonator, technology. Several challenges were overcome throughout the development process. First, the existing architecture, which achieved ±100-ppm stability, was re-architected to realize over 2X improvement in frequency stability. This required precise and innovative analog and RF design techniques, meticulous layout and complete knowledge of all temperature-dependent devices and parameters within the design.

Given the new architecture, much more sophisticated test algorithms were also developed to enable high-volume and high-throughout production as each and every single device requires accurate frequency trimming and temperature compensation. Further, and unlike XOs that are assembled in ceramic packages, the 3LG family of oscillators is assembled in plastic. Thus, a novel and patent-pending post-processed shielding technology was developed to maintain high-frequency stability within the comparatively less forgiving plastic assembly.

Yet the surprise was not in achieving ±50-ppm stability, but in achieving

The team involved

A truly multi-disciplinary team was involved in the successful development of the 3LG CrystalFree family of solid-state oscillators. The team members not only included some of the best analog silicon designers, but also some of the world’s best process engineers to create the post process shield and test engineers to develop a low cost high volume test platform capable of shipping millions of these oscillators at minimal test cost.

How long did it take?

The first CrystalFree solid-state oscillators, with ±500-ppm stability, entered the market in 2005 with a focus on USB applications. In fact, those initial products were based on over 4 years of research and development. Over 5 years later, the 3C Series of ±100-ppm oscillators were released in 2010. This generation of ±50-ppm 3LG oscillators, achieving 2X improvement in precision over the 3C Series, took almost 2 years from the initial design efforts to market introduction. Thus, in aggregate, it has taken over 11 years of development to achieve the performance now offered by the 3LG product family.

Christina Nickolas