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VCXO (Voltage-Controlled Crystal Oscillator) Product Introduction

2025-05-09

1. Product Overview

The Voltage-Controlled Crystal Oscillator (VCXO) is a type of crystal oscillator that adjusts its output frequency by varying an external control voltage. Combining the high stability of a crystal oscillator with frequency tunability, VCXOs are widely used in applications requiring precise frequency control.

VCXOs utilize a quartz crystal as the resonant element, offering a high Q-factor for stable frequency output. By introducing a control voltage, the VCXO can fine-tune its frequency within a small range, making it ideal for clock synchronization and signal adjustment.

2. Working Principle

The core components of a VCXO include a quartz crystal and an oscillation circuit. When the control voltage changes, the capacitance of a varactor diode adjusts accordingly, altering the total capacitance of the oscillation circuit. This variation in capacitance causes a slight shift in the oscillation frequency. A higher control voltage results in a larger frequency deviation. Although the tuning range is relatively small, it is sufficient for high-precision applications.

3. Key Features

High Frequency Stability: VCXOs use quartz crystals to ensure excellent frequency stability, making them suitable for precision clocking and synchronization systems.

Frequency Adjustability: The output frequency can be fine-tuned within a specified range (typically a few ppm to tens of ppm) by adjusting the control voltage.

Low Phase Noise: VCXOs exhibit low phase noise in high-frequency applications, ensuring high-quality signal output.

Excellent Temperature Stability: VCXOs maintain high accuracy and stability across a wide temperature range (-40°C to +85°C), making them suitable for harsh environments.

4. Applications

Communication Systems: VCXOs are widely used in wireless base stations, switches, and fiber-optic communication equipment for clock synchronization and precise signal control.

Networking Equipment: Routers, switches, and other network devices rely on VCXOs to generate high-precision clock signals, ensuring accurate data transmission and synchronization.

Audio/Video Equipment: In high-end audio and video processing systems, VCXOs provide low-jitter clock signals to maintain synchronization and enhance playback quality.

Test & Measurement Instruments: VCXOs play a critical role in frequency counters, signal generators, and other precision instruments for accurate frequency generation and adjustment.

Satellite & Navigation Systems: Due to their high-precision tuning capability, VCXOs are used in GPS and satellite communication systems for precise frequency control.

5. Product Specifications

Frequency Range: 1.25 MHz to 1500 MHz (model-dependent)

Frequency Tuning Range: ±50 ppm to ±100 ppm

Control Voltage Range: 0V to 5V (varies by design)

Operating Temperature Range: -40°C to +85°C

Phase Noise: -135 dBc/Hz @ 1kHz offset @ 50MHz

Supply Voltage: 1.8V / 2.5V / 3.3V / 5.0V

6. Conclusion

With outstanding frequency stability and tunability, VCXOs play a vital role in modern communication, networking, audio/video, and test & measurement applications. Their flexible voltage control provides an effective solution for systems requiring frequency adjustment. Whether in extreme temperatures or high-precision synchronization scenarios, VCXOs demonstrate superior performance.

Hangjing offers VCXO products in various packages, with low phase noise and multiple output types (CMOS, LVDS, LVPECL).