The SCO is an all-silicon oscillator that does not require an external frequency reference for frequency generation, and instead generates its frequency from an internal LC oscillator. As the name implies, the SCO is self compensated and achieves its stability without the need for analog or digital compensation. The stability is achieved with a low cost, Room Temperature Only (RTO) trimming routine.
The SCO can achieve a frequency stability of 25ppm over a temperature range of 0ºC to 70ºC, which is inclusive of initial accuracy and temperature, supply, and load variations. This stability is a breakthrough for all-silicon oscillator technology and allows for a viable alternative to quartz or SiMEMS based oscillators.
A clock oscillator in any electronic system uses a mechanical resonator, typically quartz with SiMEMS being a newer entrant that has to be hermetically sealed. A conditioning ASIC is packaged together with the resonator to achieve the required oscillator clock output. By generating its frequency via an internal LC oscillator, the SCO eliminates the need for a mechanical resonator and is a single silicon die. The SCO has the advantage of being lower cost versus mechanical resonator based oscillators as well as being more robust to shock and vibration as there are no moving structures.
SWS has leveraged its experience in developing turn-key timing solutions for companies in developing the SCO, said Hisham Haddara, Ph.D, CEO at SWS. With the SCO, all-silicon oscillators finally have the performance needed to be a viable, low cost alternative to quartz and SiMEMS oscillators.
The SCOs output frequency is factory programmable and can generate frequencies from 1MHz to 133MHz. Operating voltage can be set to 1.8V, 2.5V or 3.3V, with current consumption in the single-digit mA range for frequencies up to 100MHz. The noise performance of the SCO is very good at 125MHz the period jitter is 2ps RMS and the phase jitter is 0.7ps RMS (integrated 1MHz to 20MHz).
The SCO is a miniature silicon die that can be packaged in plastic with industry standard footprints. Alternatively, the SCO can be packaged with other Integrated Circuits (ICs), allowing these ICs to eliminate the external frequency reference. Additional clocking circuitry, such as frequency synthesizers, can be easily added to the SCO creating a highly integrated, single chip timing solution.
With the architecture of the SCO and the RTO trimming, SWS has developed a solution that can be easily and cost effectively implemented to provide an integrated clocking solution, said Ayman Ahmed, Division Manager for Timing Products at SWS.
SWS is currently preparing samples of its SCO technology for delivery in Q2 2011 to interested partners.
SWS at the Frequency Control Symposium
SWS will be presenting more details on its SCO at the Frequency Control Symposium in San Francisco being held next week, May 1st through 5th. On Tuesday afternoon SWS will present its SCO paper - A Highly Stable CMOS Self-Compensated Oscillator (SCO) Based on an LC Tank Temperature Null Concept.
SWS in Brief
Si-Ware Systems (SWS) is an independent fabless semiconductor company providing a wide spectrum of product design and development solutions, custom ASIC development and supply as well as standard products.
SWS leverages its highly talented teams in MEMS design and development as well as Analog/Mixed-Signal and Radio Frequency (RF) Integrated Circuits (ICs) to provide highly innovative solutions and products in different areas ranging from PLL based timing circuits, sensor interfaces, frequency synthesis, data converters, RF front-ends, and MEMS based sensor systems. For more information, please visit http://www.si-ware.com.
Ayman Ahmed, Division Manager, Timing Products
Tel. +20 2 2268 4704