- Buyers Guide
Pat Hindle, MWJ Editor
MEMS Oscillators - Is it Time?
For almost 100 years, quartz based oscillators have dominated the precision timing market due to their high stability over temperature, low noise, low current and relatively low cost. However, they do have drawbacks such as susceptibility to shock/vibration/EMI, high temperatures/rapid changes in temperature, activity dips/hysteresis and degradation at higher frequencies. While MEMS devices have been around for a while, the traditional electrostatic type of device has several issues that prevent it from being successful in high precision timing.
Sand9 has developed a piezoelectric MEMS device that overcomes most of these issues and now is poised to compete with the traditional precision quartz devices. The piezoelectric MEMS device has low noise, low current and thermal stability of 200 ppm (versus 3000 ppm for electrostatic devices). They have just released their temperature compensated MEMS oscillator with stability of +/- 5 ppm over -40 to +85 deg C. The 125 MHz device has 300 fs jitter (12 kHz to 20 MHz) and is stable under extreme vibration and shock conditions. It comes in a compact LGA package (3.2 X 2.5 mm) but future versions will utilize wafer level chip scale packaging for minimal footprint. The devices are aimed at the Communications Infrastructure, Test and Measurement and Military markets.
There are several new oscillator technologies that I have seen lately, so it will be very interesting to see how well they do in the market. Our November cover story features a new technology, the Mobius strip resonator, developed by Drs. Rohde and Poddar at Synergy. Our Oct issue featured an article from OEwaves who has developed a high performance RF photonic oscillator. Let me know if you see any other new technologies developing in the oscillator market.