PCB DESIGN
The schematic and layout of PCB is designed using the software DIPTRACE. The chip is placed in the center-right and the connection to the speaker is added on the right side. There are two voltage regulators one for AVDD and one for DVDD, to give some isolation from digital switiching to analog processing. Various decoupling capacitors are added between the source and the ground.
The most important consideration for the PCB design of an audio amplifier is ensuring that the power lines are routed carefully. Given the fact that the load is typically of the order of a few Ohms for audio amplifiers, any resistance in the power lines will appear in series with this and significantly affect power efficiency (and the amount of power delivered to the load). Therefore, the power lines on the PCB need to be made sufficiently wide so that their resistance is negligible (less than 1%) compared to the load resistance.
Wires that carry these high frequency signal will radiate these if the wires are sufficiently long. This radiation could interfere with other instruments nearby and can be considered to be a case of Electro-Magnetic Interference (EMI). The only way to mitigate this effect is to reduce the length of the wires connecting the chip to the speaker as much as possible.
The PCB Schematic:
Figure 1: Schematic of PCB
The PCB Layout:
Figure 2: Layout of PCB