We how to choose the size of the filter capacitor?First of all, the filter capacitor is not the bigger the better. The specific capacitance value to choose depends on the main working frequency on your PCB and the harmonic frequency that may affect the system. The number is selected according to your own needs, and then according to the actual debugging situation. Select the capacitance of the filter capacitor. If the main operating frequency on your PCB is relatively low, it is also possible to add a few capacitors appropriately, one to filter out ripples and one to filter out high-frequency signals. If there is a relatively large instantaneous current, it is recommended to add a relatively large tantalum capacitor.

In fact, the filter capacitor should also contain two aspects, which are also the large capacitance value and small capacitance value mentioned by you, which are used for decoupling and bypass. Theoretically, the larger the filter capacitor used for the power supply, the better. Generally, large capacitors filter low frequency waves, and small capacitors filter high frequency waves. The large capacitor is used to stabilize the output, and the voltage across the capacitor cannot change suddenly, so the output can be smooth. Small capacitors are used to filter high frequency interference to make the output voltage pure.

How to choose the size of the filter capacitor?