Microelectromechanical systems use silicon processing techniques to craft resonators on CMOS chips, replacing quartz crystals for time bases. But silicon is not as stable a material as quartz, requiring chip makers to add active temperature compensation circuitry that increases power consumption. Silicon Clocks Inc. (Fremont, Calif.) claims to have solved the stability problem with a passive approach that compensates for temperature with materials that consume no power but achieve results rivaling quartz crystals. Quartz crystals typically provide frequency stability from 0.25 to 1 parts per million per degree Celsius compared to 15 to 30 ppm/degreeC for typical MEMS resonators. The new temperature compensation scheme, called CMEMS-ZeroThermal, delivered a 30-fold improvement in frequency stability of 0.5 to 1 ppm/degreeC, the company claims.