An OCXO (Oven Controlled Crystal Oscillator) is a type of crystal oscillator that maintains a constant temperature using an oven, minimizing frequency changes due to environmental temperature fluctuations, resulting in greater frequency stability.

However, the oven requires continuous operation, leading to longer startup times compared to XO and TCXO (from milliseconds to several minutes) and higher power consumption (up to a few watts, compared to milliwatts for TCXO).

1. Key OCXO Parameters

        Frequency Stability: ±0.1ppm to ±1ppb

        Aging Rate: ±0.2ppm/year to ±20ppb/year

        Power Consumption: 1.5W to 2W (at +25°C)

2. DOCXO (Double OCXO)

For higher precision (±0.1ppb to ±0.05ppb), a DOCXO places an OCXO in a second oven, improving temperature stability to ±0.10°C, compared to ±1°C in a standard OCXO.

3. Crystal Cutting Types

The choice of crystal cutting affects temperature stability. SC cuts have a lower frequency-temperature slope than AT cuts, making them more stable under varying temperatures.

4. Advantages of OCXO

    High frequency and temperature stability

    Low phase noise, especially at low offset frequencies

    Excellent short-term frequency stability

    Low jitter (sub-hundred fs)

5. Disadvantages of OCXO

    High power consumption, unsuitable for battery-powered applications

    Larger size (e.g., 25×22×12.1 mm)

    High cost, often significantly more expensive than TCXO

6. SJK Crystal OCXO Sizes and Part Numbers

    SMD: 1X (9.7×7.5×4.1 mm), 9X (14.7×9.5×6.5 mm), 5X (25.4×22.1×11.0 mm)

    THT: 1X (20.3×12.7×11.0 mm), 9X (21.0×21.0×11.0 mm), 6X (25.4×25.4×13.0 mm), 6X (36.3×27.2×13.0 mm)

7. Applications

OCXOs are widely used in communication, smart grids, industrial equipment, navigation, and military/aerospace applications, with ongoing advancements in miniaturization, precision, reliability, and power efficiency.