SiTime Corporation

07/14/2025 | News release | Distributed by Public on 07/14/2025 18:17

TCXOs vs OCXOs: Which One Is Right for Your Next Design

Image

From smartphones and satellites to 5G base stations and industrial systems, Precision Timing devices are the heartbeat of every design-synchronizing subsystems, managing data flow, and ensuring reliable operations. Even minor timing errors can trigger communication failures, data corruption or system crashes.

To maintain accuracy, engineers rely on high-performance solutions like ultra-stable oscillators, phase-locked loops (PLLs) and advanced timing analysis tools. Among the most critical timing components are temperature-compensated oscillators (TCXOs) and oven-controlled oscillators (OCXOs)-both engineered to deliver stable frequency across temperature fluctuations.

This guide helps system engineers evaluate high-level tradeoffs to choose the right oscillator based on frequency stability, power budget, board space and system cost.

Understanding TCXOs and OCXOs: Key Differences

Temperature variation is one of the biggest challenges for oscillator stability. Frequency stability (F/T) is typically measured in parts per million (ppm) or parts per billion (ppb), and system designers closely watch the frequency slope over temperature (dF/dT) when choosing a timing component.

Both TCXOs and OCXOs are designed to combat temperature variations:

  • TCXOs have temperature compensation circuitry and are favored for their compact size and low power consumption, making them ideal for GPS receivers, RF transmitters and network synchronization in space-constrained applications.
  • OCXOs can have temperature compensation circuitry similar to TCXOs, but they enclose the resonator in a heated mini-oven, keeping it at a constant elevated temperature. This "ovenization" shields the oscillator from external thermal fluctuations, delivering superior frequency stability-but the trade off is greater size, power, warm-up time and cost. OCXOs are ideal for applications such as 5G core and edge, datacenter time servers and switches, and satellite ground equipment.

With each successive generation, TCXOs have grown more stable and OCXOs have become smaller and more efficient, closing the performance gap between them. Many of these advancements stem from silicon MEMS-based Precision Timing, driven by innovations in analog circuitry and packaging. Recent advances have brought MEMS TCXO performance into new territory, achieving frequency stability as tight as ±5 ppb (.005 ppm), expanding their utility into higher precision applications once reserved for OCXOs. In addition, OCXOs are beginning to encroach on the size and power advantages of the TCXO.

Image
While TCXOs and OCXOs are both designed to combat temperature changes and provide precision timing, there are tradeoffs in stability performance, size, power and cost between these two types of devices. Advancements in MEMS Precision Timing technology are changing the performance boundaries.

Why MEMS-Based Timing Devices Are Game Changers

In choosing a TCXO or OCXO the materials matter. While quartz is commonly used, it can be problematic in applications that require:

  • Operation beyond +85°C, up to +105°C (While there are Quartz options at this range, typically they offer no better than ±10 ppb frequency stability)
  • Resilience to fast temperature ramps
  • Low dF/dT under dynamic thermal conditions
  • High immunity to vibration and power supply noise
  • Stable performance when placed near heat-intensive components like power supplies, RF modules or high-speed processors

Designers face a critical choice: continue using legacy quartz-based TCXOs and OCXOs or adopt MEMS Precision Timing solutions. MEMS -based oscillators, built with ultra-pure monocrystalline silicon resonators, deliver advantages over quartz in these areas.

MEMS Innovation Meets Rigorous Demands: Datacenter, Networking and Communications

Advanced datacenter, networking and communications applications are pushing traditional timing components to their limits. For instance, workload management in AI datacenters is critical to maintaining performance, efficiency and uptime. If tasks are not precisely scheduled and synchronized, it can lead to resource issues, data corruption or workload interruption-especially in large-scale parallel processing environments. Frequency precision ensures that timing signals remain stable and synchronized across systems, enabling smooth coordination of compute-intensive operations. Without accurate timing, even minor discrepancies can cascade into major failures or costly downtime.

In these dynamic settings, quartz-based TCXOs and OCXOs often struggle to maintain frequency precision-particularly in protocols such as IEEE 1588, where even minor timing deviations can degrade synchronization. MEMS OCXOs are the go-to solution for their superior stability but in some cases low-end OCXOs can be replaced with MEMS TCXOs and large, expensive and power hungry, high-performance OCXOs can be replaced with smaller, lower power and more integrated solutions.

Image
MEMS-based TCXOs and OCXOs offer improved performance in demanding use cases such as in AI datacenters, networking and communications.

MEMS Innovation Meets Rigorous Demands: GNSS

Holdover is the ability of a timing system to maintain accurate time or frequency in the absence of its primary reference signal, for instance during GNSS signal loss due to severe weather. TCXO-based systems may drift several microseconds within minutes of losing its reference signal, while some OCXOs can hold to microsecond precision over much longer periods.

SiTime's Epoch OCXOs are particularly well-suited for holdover scenarios. What sets Epoch apart is its combination of tight frequency stability, low phase noise and efficient thermal design, all in a compact and power-conscious footprint. This enables longer and more predictable holdover durations compared to traditional OCXOs, which may consume more power or drift more significantly over time. In addition, the SiTime TimeFabric™ Software Suite delivers IEEE-1588-2019-based precision timing synchronization and extended holdover: sub-microsecond synchronization and 24-hour holdover without hardware upgrades, additional power consumption, or increased complexity. System designers can build more resilient timing architectures that reduce reliance on constant GNSS connectivity while still meeting stringent performance and reliability requirements.

Image
SiTime Epoch OCXOs have 2X better holdover than quartz in real world conditions to ensure service continuity even when the signal is dropped.
Image
IEEE 1588 Synchronization Solution Meets ITU-T G.8273 Class D Requirements for SiTime TCXOs and OCXOs.
Image
SiTime Endura Epoch MEMS OCXO delivers stability, size and power benefits. At 1 ppb stability over temperature and 420 mW power in a 9x7 mm package, it delivers 20X better stability, 2X lower power, 9X smaller footprint over competing quartz devices.

How MEMS Is Changing the Face of Precision Timing

Next-generation timing solutions are turning to MEMS technology, built on ultra-pure silicon resonators. These resonators are hermetically sealed in a vacuum through epi-seal process, which protects the components from moisture, contamination and aging-ensuring reliable performance over years of operation.

A key advantage of MEMS-based timing is multi-resonator integration. Unlike quartz, MEMS enables the design of resonators with different temperature coefficients in the same package, allowing engineers to fine-tune performance across wide temperature ranges.

MEMS innovation doesn't stop there. SiTime has developed radically new architectures that depart from traditional quartz-based designs:

  • DualMEMS™ Resonators: Two independent MEMS structures work together to deliver enhanced mechanical stability, thermal robustness and redundancy. This setup allows for automatic calibration and seamless switching to maintain accuracy under mechanical stress or thermal variation.
  • TurboCompensation™ Technology: Real-time correction of frequency drift using advanced temperature sensing and algorithms that dynamically adapt to environmental conditions.
Image
Mixed-Signal CMOS Precision Timing oscillator with integrated DualMEMS resonators and Turbo Compensation technology through Temp Sense temperature detection circuits.

Backed by features like dual-resonator temperature detection circuits (TDCs), high-resolution fractional-N PLLs, and fully digital temperature compensation, MEMS-based oscillators from SiTime are delivering timing precision once thought unattainable in harsh environments. These advanced architectures unlock a new class of timing devices that combine the size and power efficiency of TCXOs with the performance typically reserved for OCXOs-delivering reliability in datacenters, networking and communications, 5G, aerospace and defense, automotive, industrial, IoT and much more.

TCXO or OCXO: The Right Fit

TCXOs are closing the performance gap with OCXOs, just as OCXOs are shrinking in size and power. This convergence is driven by silicon MEMS technology, along with advances in analog design and packaging. As these devices advance, system designers gain new flexibility in choosing high-precision timing solutions, to achieve greater performance and reliability in their next design.

Learn more about SiTime MEMS-based Elite RF Differential Super-TCXOs®, Epoch OCXOs and TimeFabric Software Suite.

SiTime Corporation published this content on July 14, 2025, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on July 15, 2025 at 00:18 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at support@pubt.io