Lowering the Total Cost of Timing with the Increased Reliability of IC-Based OCXOs

Ben Reardon, Ullas Kumar, Mary Carbin

Abstract:	Quartz Crystal based oscillators, specifically Oven Controlled X’tal Oscillators (OCXO), continue to dominate applications that require high quality factor and high stability. The complexity of the thermo-mechanical design, the intricacies of manufacturing low profile solutions with reliable discrete components and the laborious testing and qualification process add cost to an OCXO. The reliability of these devices is extremely challenging since OCXOs operate at high internal temperatures continually over their lifetime. Recent developments in OCXO technology using Integrated Circuits are breakthroughs in the industry allowing significant reduction in manufacturing complexity which in turn significantly improves reliability. In addition, an IC-based OCXOs reduce the overall size and power requirements compared to traditional discrete OCXO designs. Introduction of Digital Signal Processing Techniques is improving OCXO performance by an order of magnitude compared to similar traditional OCXO package profiles. The knowledge and experience in oscillator design over many decades are now being transferred into the digital domain, thanks to the powerful processing engines which make it possible. Residual thermal effects, hysteresis, power supply variations and other system effects can now be compensated while the system is in operation. Ageing of the system, measured against a known reference, can also be corrected on the oscillator level. Support for system level signals like 1 Pulse Per Second (1pps) input and output in an OCXO can ease system integration challenges. Such system level support functions simplify the complexity of characterization of the equipment (e.g. Temperature Cycling and Ageing characterization) and saves cost. There are a number of applications that demand extreme operating temperatures and Oven Control methods have traditionally been limited in achieving such temperatures. Innovative crystal cuts and new thermally insensitive components are being evaluated as potential solutions. There is also development in lower cost Temperature Controlled X’tal Oscillator (TCXO) technology to improve stability. Techniques that are used in the Oven Control methods are being applied in temperature compensation to further reduce the residual effects and achieve performance in a low-power TCXO that is comparable to some higher cost OCXO.
Published in:	Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting January 25 - 28, 2016 Hyatt Regency Monterey Monterey, California
Pages:	52 - 59
Cite this article:	Reardon, Ben, Kumar, Ullas, Carbin, Mary, "Lowering the Total Cost of Timing with the Increased Reliability of IC-Based OCXOs," Proceedings of the 47th Annual Precise Time and Time Interval Systems and Applications Meeting, Monterey, California, January 2016, pp. 52-59. https://doi.org/10.33012/2016.13145
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