What Is a Crystal Oscillator? Understanding the ''Heartbeat'' And Core Applications of Electronic Products in One Article

We pick up our phones every day to watch videos, use navigation while driving, and turn on the air conditioning when we get home. Behind these smooth experiences, there is a nail cover or even a tiny electronic component - a crystal oscillator. Many people have never heard of its name, but without it, all electronic devices would simply 'go on strike'. It is like the heartbeat of electronic devices, outputting precise frequencies with stable vibrations, supporting the operation of the entire modern electronic world. Today we will talk about this inconspicuous yet incredibly important small component.

1. What is a crystal oscillator? Why can it generate frequency?

The full name of crystal oscillator is "quartz crystal resonator", and the core material is natural or artificially processed quartz crystal. This type of crystal has a very special physical effect called the "piezoelectric effect": if electricity is applied to both ends of the crystal, it will undergo deformation; Conversely, if pressure is applied to the crystal to deform it, it will generate electricity at both ends.

Engineers utilize this effect to cut quartz crystals into thin sheets of specific thickness, attach electrodes, and package them. After being powered on, the crystal will continue to vibrate stably, and in turn, the vibration will continue to output electrical signals, ultimately outputting a signal with extremely stable frequency - this is the principle of crystal oscillator providing precise frequency to electronic devices. Simply put, a crystal oscillator is like a "ruler" in the electronic world, and all timing, communication, and timing must be aligned with this ruler, not even a little bit off. The size of crystal oscillators on the market is getting smaller and smaller, to the point where they can reach 1.2 × 1.0 millimeters, even smaller than sesame seeds, fully meeting the needs of small devices such as smartphones and smartwatches; At the same time, there are also large-sized packages to meet the needs of special scenarios such as industry and automobiles.

2. Does every electronic device have a crystal oscillator? What is it doing inside?

Many people don't know that your phone actually has more than one crystal oscillator, usually at least two, each responsible for different functions.

Firstly, the core function is to provide clock signals to the processor when the "system heartbeat" occurs. The processor is like the brain of an electronic device, where all operations and instructions must follow a unified rhythm, and the frequency output by the crystal oscillator is the benchmark for this rhythm. If there were no crystal oscillator, the various cores of the processor would not have a unified beat, and data transmission and computation would be chaotic, making it impossible for the device to start.

Secondly, the communication function cannot be separated from the crystal oscillator fixed frequency. We use Bluetooth to connect headphones, WiFi to access the internet, and 5G to make calls. All wireless signals need to be loaded onto a specific frequency carrier for transmission, and a crystal oscillator is used to set the frequency of the carrier. If the frequency of the crystal oscillator is not accurate, the phone will not be able to detect the signal and Bluetooth will frequently disconnect.

Finally, there is the timing function. The accuracy of the time on your phone depends entirely on the crystal oscillator. Even the cheapest ordinary quartz crystal oscillator has a frequency deviation of no more than 5 parts per million per day, which translates to a time error of less than 0.5 seconds per day; If it is a higher precision temperature compensated crystal oscillator, the annual error is less than one second, much more accurate than ordinary clocks.

In addition to consumer electronics, the industrial, automotive, and aerospace fields cannot do without crystal oscillators. The automated production lines of factories, the autonomous driving chips of new energy vehicles, and the signal reception on satellite navigation all require high-precision crystal oscillators to ensure operation. Even a frequency difference of one millionth may lead to equipment failure.

3. Not all crystal oscillators are the same, there are different considerations when choosing a crystal oscillator for different scenarios

Many people think that a crystal oscillator only needs to be able to "output frequency", but in fact, the requirements for a crystal oscillator vary greatly in different scenarios. In the industry, crystal oscillators are generally classified into different types based on accuracy and functionality:

The most common one is the "ordinary quartz crystal oscillator", which is cheap in price and has an accuracy generally within 10 parts per million. It is sufficient to meet the frequency requirements of scenarios such as remote controllers and ordinary small appliances, and is the most widely used crystal oscillator on the market.

If it is a scenario with higher precision requirements, such as navigation GNSS, "temperature compensated crystal oscillator (TCXO)" will be used. This type of crystal oscillator comes with a temperature compensation circuit, because the vibration frequency of quartz crystal changes with temperature. The temperature compensated crystal oscillator can offset the frequency deviation caused by temperature, and the accuracy can reach within one millionth. Even at extreme temperatures ranging from -40 ℃ to 85 ℃, the frequency can remain stable, making it widely used in automotive electronics, communication base stations, and other scenarios.

There is also a higher precision "Constant Temperature Crystal Oscillator (OCXO)". This type of crystal oscillator places the crystal in a constant temperature package to prevent temperature changes from affecting frequency at the root, with an accuracy of up to one billionth. It is generally only used in professional scenarios such as satellite communication, base station clocks, and metering equipment that require extremely high frequency accuracy, and its price ranges from tens to thousands of yuan.

4. Why are domestic crystal oscillators becoming increasingly recognized now?

In the early years, the high-end crystal oscillator market was basically monopolized by Japanese and American brands, and most domestic crystal oscillator companies could only produce mid to low end products. In the past decade, the domestic crystal oscillator industry has made rapid technological breakthroughs, and has been able to produce high-end crystal oscillators that meet automotive specifications. Not only can the accuracy meet the requirements, but the stability also meets international standards, and the price is much lower than imported products.

Especially with the explosive growth of new energy vehicles, a new energy vehicle requires dozens of crystal oscillators, and the production capacity and cost-effectiveness advantages of domestic crystal oscillators are reflected. More and more car manufacturers are choosing domestically produced crystal oscillators, which not only reduces costs but also avoids supply chain bottlenecks.

Conclusion

Crystal oscillator is an inconspicuous small component, but it supports the entire modern electronic information society. From the phones in our pockets to the satellites in space, from the air conditioning at home to the new energy vehicles running on the road, the stable operation of every electronic device relies on the precise frequency output of this small component. Many times we may not feel its existence, but it is like the invisible cornerstone of the electronic world, silently supporting the technological convenience we are accustomed to. With the development of 5G, artificial intelligence, and new energy vehicles, the demand for high-precision crystal oscillators will continue to increase. Domestic crystal oscillators will also replace imports in more fields and become an indispensable part of the global electronics industry chain.