22-04-2020 | | By Nnamdi Anyadike
Oven Controlled Crystal Oscillators (OCXOs) are rapidly gaining ground across a range of high performance applications. An OCXO is a temperature-controlled device that maintains a quartz crystals’ constant operating temperature. This prevents changes in the specified frequency due to variations in ambient temperature. OCXOs improved stability is achieved by maintaining a near constant crystal temperature regardless of the ambient temperature the oscillator is experiencing. Inside an OCXO, there is a heater circuit in addition to the oscillator circuit. This heater circuit can be configured in many different ways, but the most common is a proportionally controlled oven that uses a heating element to heat the crystal and a thermistor to sense the temperature of the crystal.
At the end of March, Magic Xtal Ltd the Omsk Russia based research and production enterprise solely dedicated to the development and manufacturing of advanced OCXOs, presented its brand new OCXO ‘MXO37’ series. The series features extremely low operating power of only up to 70 mW at an ambient temperature of 25°C. Described as, “the world's smallest highly professional OCXO”, it is designed for use in applications where there is a bottleneck in the power supply, including portable data communication, mobile test equipment and any type of battery-based application. Specifications include: stability of up to +/-10 ppb from -40 to + 85°C; a warm-up time of only 30 seconds; and a phase noise value of -165 dBc / Hz. Other highlights also include the fundamental oscillation of the quartz up to 100 MHz and its ultra-low aging of 0.1 ppb per day. The operating voltage can be specified at 5 volts or 3.3 volts. “This extraordinary performance data in the TO-8 housing was only made possible by Magic's groundbreaking invention of the ‘internal heating resonator (IHR)’ technology”, said the company.
In April, IQD a market leader in the frequency control market and part of the Würth Elektronik eiSos GmbH & Co group announced the launch of its new series of GNSS-disciplined OCXOs, the IQCM-112. The design incorporates an internal GNSS receiver with a 1PPS output. This is compatible with an external GPS, GLONASS, BeiDou and Galileo source. When coupled to an external aerial antenna via the incorporated SMA connector, the 10-MHz OCXO in the event of the loss of the GNSS signal will switch-in with a holdover capability of 1.5 µSeconds for a 24-hour period. This is sufficient to maintain lock until restoration of the reference signal. The standard operating temperature range is -20° to 75° C but it is also available with a -40° to 85° C operating temperature range. The required power supply is 5V with a standard HCMOS output. Current consumption is 2A maximum during warm-up with this reducing to 1A once the steady-state condition is reached. A built-in internal alarm indicates lock failure and subsequent restoration of signal. The unit incorporates a serial connection for more detailed interrogation of the device’s performance. The IQCM-112 series is intended for a range of applications including land-based telecommunications systems and marine-based navigation systems. IQD’s OCXO range includes frequencies up to 100MHz with a wide choice of package sizes, supply voltages and outputs available.
Abracon LLC, the manufacturer of passive and electromechanical timing, synchronization, power, connectivity and RF solutions, recently announced the availability of two new SMD OCXO series, the AOC2012 and AOC1409. “With 5G around the corner, compact precision-timing solutions that support full industrial operating temperature range, along with ultra-low phase noise performance have become essential,” said Abracon VP of Engineering Syed Raza. “Low phase noise is the key in maintaining low bit error rate and excellent sensitivity, which are essential in next-generation radio architectures.” The AOC2012 and AOC1409 solutions both employ a precision SC-cut high “Q” quartz crystal resonator design, coupled with precision temperature monitoring and control circuitry. This combination enables Abracon to meet Stratum 3 and 3E requirements with this family of OCXOs. The AOC2012 series is available at standard carrier frequencies of 10MHz, 12.8MHz, 19.44MHz and 25MHz.The AOC1409 series is offered in a 14.90 x 9.70 x 7.00mm SMD package and is optimized to operate over the industrial temperature range of -40°C to +85°C.
SiTime Corp, the California based developer of oscillators, clock generators, embedded resonators and other timing solutions, is the producer of the SiT5711, which the company claims is, “the industry’s smallest Stratum 3E OCXO with ±5 ppb frequency stability and 50 ppt/°C frequency slope.” The device is engineered to provide the best dynamic performance by leveraging SiTime’s unique DualMEMS™ and TurboCompensation™ temperature sensing technology. “This OCXO delivers the most stable timing in the presence of environmental stressors such as airflow, temperature perturbation, vibration, shock, and electromagnetic interference (EMI),” the company’s Web site says. The environmental robustness of SiT5711 enables ease-of-use and simplifies system design. It can be placed anywhere on the PCB and no mechanical cover or shielding is needed for thermal isolation. No external regulators are required and no additional sealing needed for high humidity environments. The SiT5711 can be factory-programmed to any frequency between 1 and 60 MHz. In addition to the 9 x 7 mm package (the smallest OCXO available), this device is also available in common OCXO footprints such as 25 x 22 mm, 20 x 13 mm, and 14 x 9 mm to enable drop-in replacement of legacy quartz OCXOs.
A recent study into the global OCXO Market predicts that it will reach a valuation of $216.2 million, by the end of 2026. This represents a CAGR of 4.7% from the $156.2 million valuation estimated for this year. Although global competition for OCXOs is fierce, the study nonetheless believes that considerable profit can be made from the manufacturing and marketing of OCXO.