MEMS oscillators in the EMO family are RoHS compliant, with frequencies ranging from 1.000 to 125.000MHz.

MEMS oscillators are showing great potential as an alternative to quartz oscillators in many medical applications. Essentially, the output frequency on the MEMS devices is controlled by an internal resonator and an integrated programmable CMOS oscillator circuit. Their good shock and vibration properties are well suited to portable and handheld applications, as well as stationary equipment. Uses include defibrillation devices, a wide array of monitoring equipment, as well as emergency response products for rugged environments.

Recent MEMS (micro-electro-mechanical systems) resonator developments, such as improved long-term frequency stability and thermal hysteresis, have convinced some design engineers and management teams that the new technology's day has come. Since World War II, quartz crystal resonators have been the standard in frequency control because of their piezoelectric and mechanical properties. There have been other contenders, such as ceramic, silicon, and RLC resonators. But none could match the temperature stability, thermal hysteresis, and long-term stability of the crystal resonators.

The EMO family of oscillators are programmed to a specified frequency prior to shipment to the customer using a proprietary MEMS resonator design and an exclusive programming method.

As you'd expect, resonators based on quartz have limitations. They cannot suitably be integrated onto silicon CMOS wafers, their cost significantly increases when their package volume decreases, and they are vulnerable to performance degradation when subjected to severe levels of shock and vibration.

In the past, reliable performance comparable to quartz was a big hurdle to clear for MEMS timing products. MEMS resonators did not exhibit good temperature stability, thermal hysteresis, and long-term stability. Now that these issues have been solved, companies are embracing the fast-growing MEMS resonator timing devices. The Ecliptek EMO product family of progrrammable MEMS oscillators, for example, includes 12 different product series in four standard package sizes, and three supply voltages (1.8, 2.5, and 3.3Vdc). They have frequency stabilities of ± 50ppm maximum over an operating temperature range of -40 to 85C.

MEMS clock oscillators provided by Ecliptek contain a MEMS resonator, an oscillator stage, frequency-temperature compensation, a low noise phase-locked loop, and a tri-state output buffer stage. A 200-mm CMOS fabrication wafer reduces lot-to-lot MEMS resonator variation, allows for industry standard QFN (Quad Flat No-Lead) packaging, and a COL (Chip On Lead) assembly process improves reliability while reducing assembly costs. Quartz, on the other hand, cannot take advantage of these manufacturing techniques due to its mechanical structure.

Reduced inventory carrying costs and shorter time to market are key reasons why use of MEMS oscillators is on the rise. Manufacturers can now offer MEMS oscillators with a shorter lead time than either quartz's fixed-frequency or programmable oscillators. Narrowing a delivery window, limits a company's liability from a time and financial perspective. And faster delivery does not come with a higher unit cost. MEMS oscillators are available in high volume at competitive prices.

As MEMS are integrated directly with CMOS, sizes will continue to shrink and perform better with less manufacturing complexity. The overwhelming size advantage of MEMS solutions will provide an avenue for further size reductions in wireless nodes, multi-chip modules, and lead to the elimination of quartz from the PCB altogether.