How to Design for Power Decoupling? and How to Optimize?

Hello everyone! In the last time, we shared the PCB stackup of the RF board, and today we will talk about power decoupling
The power supply needs to filter the noise of the power supply through the decoupling capacitor, as shown in the figure, to prevent the noise from flowing between different devices (IC), and the power supply noise will increase the phase noise of the frequency synthesizer, reduce the receiving sensitivity of the receiver, and increase the signal Strays have many detrimental effects on circuit performance.

1. The decoupling capacitor should be placed as close to the power supply as possible;
2. The smaller the value of the decoupling capacitor, the closer it is to the power supply pin; in order to achieve decoupling of noise at different frequencies, a combination of one large and one small capacitor is often used;
3. Try to set the decoupling capacitor and the power supply on the same plane. If you can't put all the capacitors on the same plane, give priority to capacitors with small capacitance;
4. The power supply enters the IC after passing through the decoupling capacitor. Do not place vias between the decoupling capacitor and IC pins.
5. Connect each decoupling capacitor to the ground nearby, and try to avoid sharing ground vias.
6. For circuit boards with independent power layers, use independent vias to supply power for each power consumption "unit", and do not share power vias.