Accurate, reliable, ultra-stable clock signals for intelligent, connected electronics.
Precision timing provides the heartbeat of all electronics, playing a crucial role in the seamless operation and synchronization of countless devices, systems, and networks. In today’s era of intelligent and connected electronics, the demand for precise and reliable timing technology has exponentially increased with the rise of AI computing, 5G networks, cloud data centers, and the IoT. These advancements underscore the importance of precision timing in critical network infrastructure. All nodes in a network must be precisely synchronized with increasing accuracy to maximize performance and reliability. For example, 5G network nodes must be synchronized within hundreds of nanoseconds, which is ten times more stringent than required by 4G LTE networks.
MEMS-based precision timing
Precision timing technology has evolved rapidly in recent years to meet the demands of high-speed, time-sensitive networks. Microelectromechanical systems (MEMS) technology has emerged as a game- changer in the realm of precision timing. MEMS-based precision timing technology is rapidly gaining traction, disrupting century-old, legacy-dominated, quartz- based timing solutions. While quartz crystals have served the electronics industry well for decades, MEMS technology elevates precision timing to new levels of performance and reliability.
MEMS resonators are miniature mechanical systems fabricated on a microscale, typically in the range of micrometers. They integrate electronic, mechanical, and electromechanical elements to create highly stable and reliable timing components that offer several advantages over traditional quartz-based systems:
- Improved resilience: MEMS devices can withstand extreme environmental conditions, including temperature variations, airflow, shock, and vibration, making them ideal for applications that demand robust performance and reliability in challenging environments.
- Miniaturization: MEMS timing components are significantly smaller than their quartz counterparts, facilitating the development of compact, lightweight electronic devices without sacrificing performance.
- Customization: MEMS technology enables the development of programmable timing solutions to meet specific application requirements. MEMS timing devices can be programmed for 15 different parameters, such as frequency, operating temperature range, and supply voltage, while a crystal is manufactured to have a single, fixed frequency. This adaptability enables MEMS-based precision timing to be deployed across a wide array of industries and use cases.
- Enhanced frequency control: MEMS-based oscillators offer better control over output frequency, enabling more precise, stable timing. This precision plays a pivotal role in enhancing the overall performance and synchronization of electronic systems.
- Lower power consumption: MEMS devices help enable longer battery life in portable and IoT devices. In our increasingly wireless and mobile world, the low power consumption of MEMS- based timing solutions is a significant advantage.
Maintaining accuracy
Modern applications such as 5G networks, datacenters, AI, automotive safety systems, and financial technology (fintech) rely on time-synchronized networks for optimal performance. The time accuracy in these synchronized networks is obtained with a combination of a GNSS time source, a network time protocol such as IEEE 1588, and a local, extremely stable oscillator. A key function of the local oscillator is to provide redundancy if GNSS or network-based timing is disrupted.
The ultra-stable local oscillator, typically an oven-controlled oscillator (OCXO), will “holdover” the network and ensure continued, seamless network operation when upstream timing sources are disrupted and temporarily unavailable. Frequency stability, defined as the variation of frequency over temperature, is table stakes for this application. However, the length of the holdover period depends on the two key additional parameters: first, the frequency vs. temperature slope (ΔF/ΔT), and second, extremely short-term frequency stability or Allan deviation (ADEV). Lower numbers on both parameters, i.e., better numbers, will help enable a longer holdover period, which means the system can operate within spec without a GNSS time source or a network time reference.
After selecting the appropriate timing device, i.e., an OCXO or TCXO, to meet the basic frequency stability requirements, system designers will have to dig into the specification of ΔF/ΔT and ADEV as well as operating conditions to make the most informed decision. For example, in high-throughput network equipment, the negative impact of the rate of temperature change must be considered to select the local oscillator. Similarly, in a system that is deployed outdoors, the performance of a local oscillator under vibration must be considered.
New ultra-stable OCXOs outperform quartz Recognizing the critical need for greater stability and longer holdover in today’s demanding electronics applications, SiTime reimagined the holdover oscillator by developing the Epoch Platform. This platform distinguishes itself by offering twice the holdover period of conventional quartz-based solutions under common environmental stressors, enabling telecom and cloud service providers to ensure service continuity in real-world conditions.
In contrast to the Epoch Platform, legacy quartz OCXOs are inherently unreliable and prone to performance degradation in the presence of environmental stressors such as temperature changes and vibration. To date, OCXO vendors have compromised on real-world performance, reliability, size, power, and warm-up time to achieve the one attribute most OCXOs are designed to deliver—a stable clock reference.
The Epoch Platform overcomes the limitations of quartz OCXOs by integrating two MEMS resonators on the same
die. This SiTime innovation, named DualMEMS, results in the best thermal coupling and the most accurate measurement of temperature. This capability ensures 40x faster temperature tracking, a crucial attribute, especially under conditions of fluctuating airflow and rapid temperature changes. The ultra-small MEMS resonator, with its extremely low mass, mitigates the effects of g-force, resulting in 30x better vibration immunity than quartz. Pairing innovative MEMS technology with SiTime’s advanced analog circuitry results in exceptional dynamic stability, ultra-low phase noise, and a broad frequency range.
Epoch Platform OCXOs enable 12 hours of holdover, support any frequency between 10 and 220MHz, are programmable up to six decimal places of accuracy, and offer digital control with I2C and SPI interfaces for unparalleled flexibility. Designed for low power consumption, these MEMS-based OCXOs consume just 420mW, which is 3x less than quartz devices. The Epoch Platform’s small footprint (9mm × 7mm × 3.73mm) occupies 9x less area and is 3x times thinner than comparable quartz-based timing solutions, enabling a greater degree of freedom for hardware designers.
SiTime’s Epoch Platform is setting new standards in MEMS-based precision timing technology, ensuring nanosecond accuracy in critical network infrastructure. With its exceptional stability, longer holdover, high reliability, and low power consumption, the Epoch Platform is poised to revolutionize the world of precision timing, making it an indispensable technology for today’s intelligent, connected electronics.