Oven-Controlled Crystal Oscillators – OCXO’s

Suntsu OCXO’s are available in through-hole packaging with many sizes to choose from. We offer many different voltage and logic options and can provide parts with ±800ppt stability. Pick out a standard part number from the data sheets listed below or contact our sales team to request any custom parameters that you desire and we will design to your specific needs.

Oven-Controlled Crystal Oscillators use temperature-controlled chambers to keep the quartz crystal inside the oscillator at a constant temperature in order to prevent changes in the frequency due to variations in the external temperature. OCXO’s are typically used to control the frequency of radio transmitters, cellular base stations, military communications equipment, and in measurement applications where the highest frequency stability possible from crystals is needed.

SeriesImageLogicPackageStability ToVoltage(s)FrequencyReelKey FeatureDatasheet
SOCFSCHCMOS14 PIN DIP OCXO±50ppb5.0V, 9.0V, 12.0V10.000MHz - 80.000MHzN/ASmall Size
SOCFSSSINE WAVE14 PIN DIP OCXO±50ppb5.0V, 9.0V, 12.0V10.000MHz - 80.000MHzN/ASmall Size
SOC20CHCMOS20.0X20.0 DIP OCXO±10ppb5.0V, 9.0V, 12.0V1.000MHz - 80.000MHzN/AHigh Stability, Low Phase Noise
SOC25CHCMOS25.4X25.4 DIP OCXO±10ppb5.0V, 9.0V, 12.0V1.000MHz - 80.000MHzN/AHigh Stability, Low Phase Noise
SOC25SSINE WAVE25.4X25.4 DIP OCXO±10ppb5.0V, 12.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC36CHCMOS36.1X27.2 DIP OCXO±7.5ppb5.0V, 9.0V, 12.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC36SSINE WAVE36.1X27.2 DIP OCXO±7.5ppb5.0V, 9.0V, 12.0V, 15.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC38CHCMOS38.1X38.1 DIP OCXO±10ppb5.0V, 9.0V, 12.0V, 15.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC38SSINE WAVE38.1X38.1 DIP OCXO±10ppb5.0V, 9.0V, 12.0V, 15.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC50CHCMOS50.0X50.0 DIP OCXO±5.0ppb5.0V, 9.0V, 12.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC50SSINE WAVE50.0X50.0 DIP OCXO±5.0ppb5.0V, 9.0V, 12.0V5.000MHz - 100.000MHzN/AHigh Stability, Low Phase Noise
SOC09CCMOS9.7X7.4 SMT OCXO±20ppb3.3V10.000MHz - 40.000MHz800Small Size, SMT
SOC14CCMOS14.4X9.4 SMT OCXO±20ppb3.3V10.000MHz - 40.000MHz800Small Size, SMT
SOC15CHCMOS15.4X10.6 SMT OCXO±5.0ppb3.3V, 5.0V10.000MHz - 20.000MHz350Small Size, SMT

Quick Summary

Features Benefit Manufacturing Location(s) Monthly Capacity
• Tight stability performance
(down to 0.05ppm)
• High stability
• Low phase noise
• Custom configurations available
• China
• South Korea
• >200k units

What is an OCXO?

OCXO stands for “Oven Controlled Crystal Oscillator.” Also referred to as a crystal oven, this type of crystal oscillator features higher-frequency stability and is considered a top performer for the precision of its frequency signals. Oven-controlled crystal oscillators rely on above-normal levels of heat to stabilize and maintain a consistent temperature. These units contain a built-in heater, which is why they are much larger than simple crystal units. Some of the most essential communications technology, such as radio transmitters, cellphone towers, military communication signals and other radio equipment, depends on the precision-grade frequency stability that an OCXO has to offer.

How does an OCXO oscillator work?

An OCXO oscillator maintains temperature stability by running a temperature-controlled chamber. The unit keeps quartz crystals at a constant temperature to avoid any variations in frequency. Given that thermal insulation and a heater are required for the quartz crystals to warm up to temperature, an OCXO is physically larger than other crystal units. The thermal insulation serves as a shield to help protect the OCXO from ambient temperature fluctuations, which is why this premium unit is touted for its precision timing.

Advantages of an OCXO

An OCXO experiences minimal frequency drift while aging, which preserves the integrity of the oscillator. These oscillators allow for precise customization for required frequency levels based simply on the angle of the crystal cuts. In addition, an OCXO does not require an excessive amount of energy to maintain the same frequency once warmed up.

Temperature stability

An OCXO experiences minimal frequency drift while aging, which preserves the integrity of the oscillator. These oscillators allow for precise customization for required frequency levels based simply on the angle of the crystal cuts. In addition, an OCXO does not require an excessive amount of energy to maintain the same frequency once warmed up.

Frequency accuracy

When it comes to frequency accuracy in an oscillator, an OCXO is the reliable choice due to its ability to avoid fluctuations in temperature once the crystal has reached its working temperature. The above-normal working temperature of an OCXO provides frequency stability and can maintain precise levels over a long time and even in adverse temperature conditions.

Overall performance

There is no question that an OCXO is the premium solution for electronics and communications technologies that rely upon precise and stable frequency signals to function properly. High-quality OCXOs deliver stable frequencies and maintain temperatures for an extended time without requiring excessive power consumption.

Power consumption

The most significant source of power consumption while operating an OCXO is in the energy required to warm it up to its working temperature. Fortunately, the OCXO stabilizes after a few moments and resumes typical power consumption. High-efficiency OCXO options are available to enable minimal power consumption and maximum performance quality even with ambient temperature variations.

Synchronizing OCXOs and Clocks

Clocks that maintain a higher degree of frequency are typically used to synchronize OCXOs. If the OCXO and the clock become unlocked or unsynchronized at any point, then the OCXO reverts to its internal controls to maintain stability during what is known as the holdover period. Thus, OCXO clocks perform consistently over time without interruptions in their timekeeping output.

How to improve the performance of an OCXO

The most crucial element in ensuring the precision and stability of a crystal’s frequency is an accurate cut. To maximize the performance of an OCXO, setting regular intervals to recalibrate the OCXO will improve its longevity. Also, the buffering circuitry and assembly of the OCXO should reflect attention to detail so that the components of the OCXO facilitate its stable operating temperature.

Setting the OCXO oven temperature

The typical oven range of temperatures for OCXOs is between 75 and 80 degrees Celsius. Higher temperature ranges may be preferable in certain industrial settings and will depend on the specific application of the OCXO.

Frequently Asked Questions

Quartz crystal oscillators have a long-standing reputation for having the best frequency stability of any other oscillator and have certainly delivered on their promise. Regardless of the inconsistent and unexpected load conditions they may occasionally encounter, quartz crystal oscillators are capable of maintaining the same frequency over time with little to no variations. This is why quartz crystal oscillators are the dependable and proven choice for use in radio transmissions, military communications and other signal technologies that rely on stable and accurate frequencies to operate effectively.

An OCXO starting at room temperature requires only a few minutes to warm up to the proper temperature before maintaining stability at that precise temperature point. The standard working temperature for an OCXO is around 80 degrees Celsius. An OCXO will maximize its power usage during the warm-up period and later decrease to a lower level once stabilized.

At the point when the external temperature is warmer than the working temperature of an OCXO, it could lose the ability to regulate the oven properly. OCXOs function based on the temperature of the internal crystal being warmer than the maximum operating temperature of the oscillator. As such, the crystal will serve as a temporary source of temperature stability until the external temperature goes down.

A rubidium oscillator uses the output signal of an OCXO to operate an atomic clock. The circuitry contained within an atomic clock is made of rubidium parts that provide the timing accuracy to control the OCXO frequency output. The rubidium oscillator continuously monitors the frequency of the OCXO against its own frequency. When the OCXO frequency varies out of line, the rubidium oscillator puts it back into line so that the atomic clock avoids any disruption in timing.

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