Technical Insight: How FCom TCXOs Power GNSS Modules

As global navigation technologies continue to advance, the demand for reliable and precise timekeeping in GNSS modules becomes more critical than ever. According to the official article from FCom Fuji Crystal, temperature-compensated crystal oscillators (TCXOs) play a vital role in delivering stable performance, especially in GPS and GNSS systems.

Why TCXOs Matter in GNSS Systems

Unlike basic crystal oscillators, TCXOs include built-in temperature compensation circuits that maintain frequency stability across a wide thermal range. This is especially important in GNSS modules where even slight timing drift can affect satellite signal acquisition and tracking.

As noted in the original content, TCXOs significantly improve time-to-first-fix (TTFF), enabling GNSS modules to lock onto signals more quickly—even in challenging environments like indoors or under dense urban canopies.

The FVT Series: Tailored for Compact, High-Performance Designs

In the application page, Fuji Crystal highlights the features of its FVT Series TCXOs, which include:

Miniature 2.0 × 1.6 mm footprint — ideal for space-constrained modules
Frequency stability of ±2.0 ppm across -30°C to +85°C
Ultra-low current consumption — only 1.5 mA typical
Clipped sine wave output suitable for GNSS receivers

These characteristics make the FVT Series an excellent choice for GPS modules, wearable devices, and portable positioning equipment that require a compact form factor and energy efficiency.

Synchronization Starts with a Stable Clock

In GNSS systems, the internal clock must stay tightly aligned with satellite signals. TCXOs reduce frequency drift, thus maintaining accurate synchronization and improving signal lock performance.

This translates into faster cold starts and better signal tracking, especially in mobile and battery-powered devices where reliability and speed are critical.

Design Considerations for Integrating TCXOs

To maximize the benefits of TCXOs in a system, FCom offers several design tips:

Use a low-noise LDO to power the TCXO, reducing supply ripple
Keep high-frequency or switching traces away from the oscillator area
Leave thermal isolation around the TCXO on the PCB layout to minimize thermal drift

These best practices help ensure consistent clock performance and better overall stability in RF designs.

Beyond GNSS: Broader Application Scenarios

While primarily intended for GNSS systems, the FVT Series TCXOs are also suitable for:

Smartwatches and fitness trackers
Drone navigation and flight controllers
Automotive telematics and in-vehicle GPS
Portable surveying and mapping equipment

In each of these use cases, TCXOs provide a robust timing backbone for precise positioning and reliable connectivity.

Conclusion: Small Component, Big Impact

TCXOs may be small in size, but their impact on GNSS system performance is substantial. The FCom FVT Series delivers reliable, temperature-stable frequency references tailored for modern, compact navigation systems.

For more detailed specifications or to explore available models, visit the FVT-6S product page.