Analysis of crystal oscillator devices on PCB

Today's circuit boards are basically inseparable from crystal oscillators, so what is a crystal oscillator? Many power electronics engineers must be familiar with the mention of crystal oscillators. The crystal oscillator is considered a "C" player in the electronics circle and is an important device that is often mentioned because it is everywhere. But do you know what crystal oscillators are on the PCB board? This article will give you a comprehensive understanding of the big secrets of small crystal oscillators, come and take a look.

The role of the crystal oscillator on the circuit board is very important. If the entire circuit board is compared to us humans, a person must have a brain, heart, and blood to work at the same time in order to function normally. The role of the crystal oscillator in the circuit board is to act as the heart. We often see that in many circuit boards, there are always crystal oscillators of different frequencies "waiting" next to a "giant black" IC chip. It is not difficult to explain why the crystal oscillator is the heart component of the circuit board. The crystal oscillator needs to start oscillating normally for the IC chip to receive it, so that the IC chip can work. It is conceivable that the IC chip is equivalent to the human brain.

Why would you rather choose an ultra-miniature chip crystal oscillator? No one has ever designed to merge the IC chip and crystal oscillator, which will reduce the space of the circuit board to a greater extent. The answer is not difficult to explain. If the crystal oscillator in the circuit board is damaged, the crystal oscillator can be directly replaced without dismantling the IC chip. On the contrary, replacing the chip and crystal oscillator at the same time will be complicated and cumbersome, and increase the cost.

Crystal oscillators are divided into passive crystal oscillators and active crystal oscillators. In the circuit board, the passive crystal oscillator requires external components such as capacitors and resistors to help start the oscillation; the active crystal oscillator has a built-in oscillation chip inside the chip and does not require external components to help start the oscillation. Therefore, from the picture, you can see that the outside of the crystal oscillator is densely covered with many capacitors, resistors and other components. It can be imagined that the chip crystal oscillator in the picture is a passive crystal oscillator.

The picture above is a reference diagram of a Bluetooth module. 12MHZ, 24MHZ, 26MHZ, and 32MHZ are all frequency points that will be used in the Bluetooth module. Many communication equipment, GPS and other 26M crystal oscillators are the most widely used. It turns out that the little one who has been given such an important role is actually the heart component of the circuit board - the crystal oscillator.

We all know that the usage rate of crystal oscillators in electronic products reaches 80%. However, crystal oscillators are a frequency component, so crystal oscillators of different frequencies have very different effects in circuit boards. When it comes to how many types of crystal oscillator frequencies there are, we cannot honestly tell you that crystal oscillator manufacturers can always meet everyone's needs for crystal oscillator frequencies. A new crystal oscillator frequency requires repeated testing and inspection before it can be officially delivered.

Our crystal oscillator can be described as powerful and very mysterious, because you can never know clearly what the function of the crystal oscillator is. Only on different platforms and different frequencies can you know the final function of the crystal oscillator. The number of crystal oscillators used in computer peripheral electronic products around us is also very considerable. Crystal oscillators are used in computer motherboards, speakers, keyboards, mice, monitors, etc.

1. The host motherboard uses crystal oscillator frequency

The crystal oscillator package commonly used in computer motherboards has not changed much in this era of miniaturization of crystal oscillators. No one requires ultra-thin and ultra-miniature computer motherboards. Therefore, 49/SMD crystal oscillators are still the best choice for computer motherboards. While the welding of the chip placement machine is convenient, compared with today's ultra-miniature 3225 crystal oscillator, the cost of selecting the 49SMD crystal oscillator for the computer motherboard is also steadily controlled. 14.318MHZ, 24.576, 25MHZ, and 27MHZ crystal oscillators are commonly used crystal oscillator frequencies for computer motherboards. They match an RTC clock crystal oscillator 32.768K. Usually computer motherboards use no more than 2-3 crystal oscillators. The 32.768K crystal oscillator that provides signals to the clock is essential. Less.

2. The monitor uses crystal oscillator frequency

The monitor also has a built-in crystal oscillator, and the accuracy requirements for the crystal oscillator are very strict. If the frequency deviation of the crystal oscillator is too large, it will directly cause the monitor to be unable to turn on and light up normally. Commonly used crystal oscillator frequencies include 8M/14.31818MHZ, 12.000MHZ, 24.000MHZ, and 28.224 MHZ

3. Bluetooth uses crystal oscillator frequency

16M crystal oscillator is a commonly used frequency for Bluetooth. Bluetooth has strict requirements for crystal oscillator packaging, which increases the cost dramatically. 3225 SMD crystal oscillator and 2520 SMD crystal oscillator are the better crystal oscillator packaging options for Bluetooth. High-end Bluetooth pairs have ultra-thin crystal oscillators. According to chemical requirements, 2016 SMD crystal oscillator and 2012 SMD crystal oscillator are also more suitable.

4. The optical drive uses crystal oscillator frequency

Nowadays, the optical drives of computer hosts have also been replaced, so the crystal oscillator frequencies commonly used in optical drives are 33.8688MHz, 16.9344MHz, and 18.432MHz. The first two are also common in the market.

5. More computer peripherals

Wireless module: 25M

2.5G/3G/4G: 40M, 44M, 32M, 14.7456M

Network transmission ADSL: 12.288MHz, 35.328MHz, 50.000MHz

6. Summary

Any electronic product requires a stable frequency to operate normally. At the same time, in addition to the huge demand for crystal oscillators in computer peripheral products, crystal oscillators are also commonly used in: smartphones, tablets, Bluetooth, digital products, and LED displays. screens, automotive electronics and high-end aviation fields. Applications in different products have different requirements. In the past few years, the crystal industry has been constantly changing with the emergence of various smart products to meet the market needs of the electronics industry. It has transformed from the previous large-volume plug-ins to Today's ultra-small and ultra-thin chip crystals. The accuracy is getting smaller and smaller, making the product more stable. This is the relevant introduction to the crystal oscillator. I hope it will be of some reference value to those who use it.