A good PCB layout practice is to keep the analog and digital grounds separate, use a solid ground plane, and keep the power traces away from the analog signals. Additionally, use a ferrite bead or a common-mode choke to filter the power supply lines.
To ensure proper power-up and power-down, follow the recommended power-up sequence: VCC, then AVCC, then DVCC. During power-down, reverse the sequence. Also, ensure that the voltage supplies are ramped up and down slowly to prevent inrush currents.
Use a 10uF ceramic capacitor in parallel with a 100nF ceramic capacitor, placed as close as possible to the power pins. This configuration helps to filter out high-frequency noise and ensures stable operation.
To minimize power consumption, use the lowest possible clock frequency, disable unused features, and use the power-down mode when not in use. Additionally, optimize the analog circuitry to minimize current consumption.
The LM49450SQ/NOPB has a maximum junction temperature of 150°C. To prevent overheating, ensure good airflow, use a heat sink if necessary, and avoid blocking the airflow around the device. Also, follow the recommended PCB layout and thermal design guidelines.