SiTime, Silicon MEMS Oscillators and Clock Generators

Low Phase Noise and Jitter of MEMS Oscillators

E-mail Print

Phase noise is a key specification that is very important to the performance and operation of the system. Wireless and GPS applications have stringent requirements for close-in phase noise (< 10 kHz offset) while serial communications applications such as SONET, Gigabit and 10 Gigabit Ethernet, SATA, SAS, FibreChannel, PCI-Express, USB have specifications for RMS phase jitter (integrated over 12 kHz to 20 MHz offsets of the carrier frequency).

The phase noise and phase jitter of SiTime's MEMS oscillators has seen dramatic improvement over the past 3 years. Newer devices, such as the Encore platform based single-ended and differential products (SiT820x, SiT380x, SiT912x, SiT500x, SiT382x) offer typical RMS phase jitter of 500 femto-seconds, and a maximum of 1 ps, integrated from 12 kHz to 20 MHz. No other MEMS oscillator offers such performance. The figure below shows an example of a phase noise plot for SiTime's MEMS oscillators.

 

The figure below shows an example of a phase noise plot for a 100 MHz MEMS oscillator (12 kHz to 20 MHz) from SiTime with 478 femtoseconds of integrated RMS phase noise.

Phase-jitter-plot

For more information, see the following application notes on clock jitter and phase noise.


Clock Jitter and Measurement
 (PDF)
This application note describes the common types of jitter encountered in high-speed systems and provides guidelines on how best to measure jitter.
 - Period Jitter
 - Cycle to Cycle Period Jitter
 - Long Term Jitter
 - Phase Jitter
 - Time Interval Error (TIE)


Phase Noise and Jitter Requirements for Serial I/O Applications
(PDF)
This application note reviews the phase jitter requirements for several applications and describes how to better analyze phase jitter requirements beyond the traditional 12 kHz to 20 MHz jitter range.