This improved performance can be attributed to the design of SiTime oscillators comprised of a MEMS resonator die mounted to a mixed-signal CMOS die housed in a plastic package. Conventional wisdom states metal can enclosures surrounding quartz oscillators provide improved protection from EMI as compared to plastic packaging. However, SiTime MEMS oscillators demonstrate improved performance over other oscillators. The analog circuits in SiTime oscillators are optimized for electrically noisy conditions and include differential circuits that inherently reject any coupled common mode noise. Other quartz and MEMS oscillator designs rely more on packaging and not on noise suppressing analog circuits. In addition, the silicon MEMS resonators are driven by electrostatic excitation, thereby making them naturally less sensitive to incoming EMI. SiTime’s architecture enables precisely tuned high Q values that reject external noise.