SPXO (Simple Package Crystal Oscillator) is usually divided into two types. One is the crystal oscillator with CMOS output, and the other is the differential output crystal oscillator. What are the differences between these two types of crystal oscillators? Next, we will introduce to you the knowledge about these crystal oscillator products in this regard.
The differential crystal oscillator (Differential Crystal Oscillator) is mainly a circuit used to generate high-frequency signals (such as clock signals) and is widely applied in electronic systems, for example, in the fields of computers, wireless communications, precision measurements, and signal processing. The common differential signal outputs include LVPECL, LVDS, HCSL, and there is also a CML signal output.
Functions of the Differential Crystal Oscillator
1. Frequency Generation: The main function of the differential crystal oscillator is to generate high-frequency and stable clock signals, which are the basis for the normal operation of electronic circuits.
2. Enhancing Anti-interference Ability: Differential signals have a relatively strong anti-interference ability. When external noise interferes with the signals, the differential signals can effectively cancel out the common-mode noise, thereby improving the stability and reliability of the system.
3. Reducing Electromagnetic Interference (EMI): Due to the characteristics of differential signals, it can effectively reduce the electromagnetic interference emitted by the system. This is especially important in high-frequency applications.
4. High-Speed Performance: The differential crystal oscillator can usually provide a relatively high frequency and a faster transition time, making it very suitable for use in high-speed digital circuits.
2. Enhancing Anti-interference Ability: Differential signals have a relatively strong anti-interference ability. When external noise interferes with the signals, the differential signals can effectively cancel out the common-mode noise, thereby improving the stability and reliability of the system.
3. Reducing Electromagnetic Interference (EMI): Due to the characteristics of differential signals, it can effectively reduce the electromagnetic interference emitted by the system. This is especially important in high-frequency applications.
4. High-Speed Performance: The differential crystal oscillator can usually provide a relatively high frequency and a faster transition time, making it very suitable for use in high-speed digital circuits.
Why Do We Need Differential Crystal Oscillators?
1. High Frequency and Stability: Many modern electronic devices require high-frequency and high-stability clock signals, and the differential crystal oscillator can meet this requirement. Currently, the highest frequency of the differential crystal oscillator products of our company's SIC brand can reach 1500 MHz, and if it is the VCXO differential signal output, it can reach up to 2100 MHz.
2. Noise Adaptability: The differential crystal oscillator performs better in a noisy environment. This is crucial for working in an environment with relatively large electromagnetic interference (such as wireless communication, precision control, etc.).
3. Reducing Signal Integrity Problems: In high-speed digital circuits, signal integrity is a key issue. The differential oscillator can provide less signal distortion and better rise/fall times, improving the signal quality.
2. Noise Adaptability: The differential crystal oscillator performs better in a noisy environment. This is crucial for working in an environment with relatively large electromagnetic interference (such as wireless communication, precision control, etc.).
3. Reducing Signal Integrity Problems: In high-speed digital circuits, signal integrity is a key issue. The differential oscillator can provide less signal distortion and better rise/fall times, improving the signal quality.
Differences Between Differential Crystal Oscillators and Ordinary Crystal Oscillators
1.Frequency Range:
Differential Crystal Oscillator: The lowest output frequency is usually 10 MHz, and the highest frequency can reach 1500 MHz or even 2100 MHz.
Ordinary Crystal Oscillator: The lowest output frequency is usually 32.768 kHz, and the highest is 220 MHz.
2. Signal Output Method:
Differential Crystal Oscillator: The output is two opposite signals (positive and negative). Usually, these two signals are connected to a differential input amplifier or receiver to eliminate common-mode interference.
Ordinary Crystal Oscillator: Usually, it outputs a single-ended signal, with only one output signal, and such a signal is more susceptible to external noise.
3. Anti-interference Ability:
Differential Crystal Oscillator: It has a strong resistance to common-mode noise and can work in a relatively poor electromagnetic environment.
Ordinary Crystal Oscillator: Since it is a single-ended output, its anti-interference performance is relatively poor and it is more susceptible to external interference.
4. Circuits Used:
Differential Crystal Oscillator: Usually, a differential amplifier or a specially designed receiving circuit is required to decode and process the differential signals.
Ordinary Crystal Oscillator: Often, a simple single-ended circuit can complete its functions.
5. Application Fields:
Differential Crystal Oscillator: It is mostly used in applications with high-frequency, high-speed, and high-reliability requirements, such as high-performance computers and communication equipment.
Ordinary Crystal Oscillator: It is generally used in application scenarios where the requirement for clock stability is not so high, such as simple electronic devices or oscillators with lower frequencies.
In summary, compared with ordinary crystal oscillators, differential crystal oscillators have obvious advantages in terms of anti-interference ability, signal quality, and applicable occasions. Therefore, they are increasingly favored in modern high-frequency and high-speed electronic applications.