Common problems and solutions for crystal oscillators!

Crystal oscillators may encounter some common problems in practical applications, which can be fixed through specific solutions. The following are common problems and corresponding solutions for crystal oscillators:

1. Material parameter selection error: If the wrong capacitance value or other parameters are selected, the crystal oscillator may not start oscillating. For example, if the MCU requires a 6PF 32.768KHz crystal oscillator and chooses a 12.5PF one, it will result in no oscillation. The solution to this problem is to replace it with a model that meets the requirements. When selecting a crystal oscillator, the requirements of the MCU should be carefully checked, and if necessary, confirmation can be made with the MCU manufacturer or supplier.

2. Internal crystal plate damage: If the crystal plate inside the crystal oscillator is damaged by drops, impacts, or other factors during transportation or use, it may not vibrate. The solution to this problem is to replace the crystal oscillator. During transportation and manufacturing processes, attention should be paid to protection to avoid damage to the crystal oscillator.

3. Mismatch of oscillation circuit: Mismatch of oscillation circuit may cause the crystal oscillator to fail to oscillate. The three key indicators that affect oscillation circuits are frequency error, negative impedance, and excitation level. If the frequency error is too large, the actual frequency will deviate from the nominal frequency, causing the crystal oscillator to not vibrate. The solution is to choose a product with an appropriate PPM value (frequency deviation per million parts per million). The magnitude of negative impedance can also affect the oscillation of the crystal oscillator. If it is too large or too small, it may not oscillate. The solution is to adjust the excitation level of the oscillation circuit to the output of the crystal oscillator by adjusting the size of Rd in the circuit. Generally speaking, the smaller the excitation level, the better. This not only reduces power consumption, but also depends on the stability of the oscillation circuit and the service life of the crystal oscillator.

4. Frequency deviation issue: When the frequency of the crystal oscillator deviates, it may cause problems such as image distortion, audio noise, and data transmission interruption. For frequency deviation, it can be solved by adjusting the load capacitance of the crystal oscillator or matching the capacitance of the circuit, or selecting a crystal oscillator with different load capacitance for replacement.

5. Improper storage environment: Long term use or storage under high temperature, low temperature, or high humidity conditions may cause deterioration of the electrical performance of the crystal oscillator, resulting in failure to vibrate. The solution is to avoid using or storing crystal oscillators in these extreme environments.

When applying crystal oscillators, it is necessary to strictly follow the design requirements and specification parameters, while paying attention to the physical protection of the crystal oscillator to ensure its normal operation. If you encounter any problems, you can use the above methods to troubleshoot and solve them.