Passive crystal oscillator, also known as quartz crystal resonator, is a passive electronic component that utilizes the piezoelectric effect of quartz crystals to generate high-precision oscillation frequencies.
Features:
1. Low cost: With a simple structure, it is the most cost-effective clock source solution.
2. Low power consumption: No need for independent power supply, completely dependent on chip driver, extremely low power consumption.
3. Compact size: Surface mount packaging (such as 3225, 2520, 2016) is ultra small and lightweight, suitable for high-density PCB design.
4. Diverse frequencies: The frequency coverage range is wide, with commonly used ranges ranging from 32.768kHz (RTC clock) to 100MHz (system clock).
5. High flexibility: The same model can adapt to multiple voltages, and the frequency can be fine tuned by adjusting the peripheral capacitance.
6. Limitations:
Relying on external circuits and improper design can easily lead to failure to vibrate or frequency offset.
Moderate accuracy and stability (usually ± 10~± 50ppm), easily affected by temperature and vibration.
Applications：
1. Consumer electronics: smartphones, tablets, smartwatches, Bluetooth earphones, remote controls.
2. Home appliances: Control motherboards for air conditioners, washing machines, microwave ovens, and set-top boxes.
3. Embedded systems: Core clock sources for microcontrollers such as 51, STM32, ESP32, etc.
4. Timing module: Real time clock (RTC), such as 32.768kHz crystal oscillator used for electronic watches and calendar chips.
5. Communication equipment: WiFi module, Bluetooth module, and reference frequency source for walkie talkies.
6. Automotive electronics: in car instruments, reverse radar, entertainment systems, etc. (requiring industrial grade temperature range).
