MEMS touted for telecomm, embedded apps
R Colin Johnson
5/9/2011 5:36 PM EDT
PORTLAND, Ore.—The increasingly stringent requirements of high-speed telecommunications, wireless networking and embedded applications can now be satisfied with micro-electro-mechanical systems, according to SiTime Inc., which announced Monday (May 9) its new SiT380X family of MEMS voltage-controlled oscillators (VCOs), offering up to 10-times better linearity and wider fine-tuning range than quartz crystals.
"Active timing components using MEMS can now shorten their lead time and increase the reliability of their applications in telecom, networking and embedded computing applications," said Piyush Sevalia, vice president of marketing at SiTime (Sunnyvale, Calif.). "We are first MEMS oscillator to offer better than picosecond phase jitter over the full offset frequency range."
VCOs actively fine-tune their frequency during operation to compensate for changes in temperature and other parameters that can throw off high-speed data transfers. The new SiT380X family of MEMS VCOs is claimed by Sevalia to be tunable over 10-times wider range (called the pull range) than crystal-based VCOs, namely plus or minus 1600 parts-per-million (compared to 200 PPM for crystals). The MEMS devices also offer better than one percent linearity (compared to 10 percent for quartz) for any frequency from 1-to-220 MHz.
The new devices—the SiT3808 (1-to-80 MHz) and SiT3809 (80-to-220 MHz)—also include programmable frequency, supply voltage, stability, and drive strength, all of which can be customized at the factory and delivered in samples within 48 hours, and in production quantities within three weeks, according to Sevalia. Both parts are pin compatible with popular crystal-based VCOs pin-outs for drop in replacement.
SiTime's chips wire-bond together a mechanical MEMS device with an application specific integrated circuit (ASIC) which are mounted together inside a standard package.
Frequencies are accurate to six decimal places, according to Sevalia, and frequency stability is as low as plus or minus 10 PPM. The MEMS VCOs also offer superior tuning slope (Kv) consistency, according to Sevalia, which minimizes variations in the performance of associated phase-locked-loops (PLLs).
Packages can be either 4-pin (3225) or 6-pin (5032 or 7050 packages) and will be available for sampling in June with full production read in the third quarter of 2011.