Refer to the schematic to ensure the placement of bypass capacitors at the device power pins and not at high logic pins. Capacitors are the most versatile components from the PCB assembly standpoint, and decoupling is one of their chief functions.
Based on the principle of decoupling capacitors, we can correctly place the decoupling capacitor at the right location of the PCB layout to gain the optimal performance. The diagram below shows the two possible options of placing the decoupling capacitor, close to the VCC pin and close to the GND pin respectively.
You may be able to implement a better arrangement if you can place your bypass capacitor on the bottom side of the board. After you determine the size of the PCB decoupling capacitor you need in your PDN, you’ll need to place it somewhere to ensure it can compensate for input voltage fluctuations.
In the past, TI (and many other semiconductor companies) recommended 1 capacitor (cap) per power pin. For DIP packages, this worked great, but other packages like BGAs were developed, this became harder and harder. With any pitch less than 1.0 mm this is nearly impossible, so now TI is trying to take a more realistic approach.
Place the capacitor between the component’s power pin and the via that connects to the power plane. This ensures smooth current flow through the plane. Daniel Beeker shared his insights, saying, “While placing the capacitor, employ the 20th wavelength of transistor switching speed.
Decoupling and bypass capacitors help stabilize power fluctuations on the PDN, ensuring consistent signal levels and maintaining a steady voltage at an IC’s power and ground pins. To assist with effective usage, we've outlined essential design guidelines for bypassing and decoupling capacitors in your next PCB.