BelaSigna 200
3.0 BelaSigna 200 Design and Layout Strategies
BelaSigna 200 is designed to allow both digital and analog processing in a single system. Due to the mixed-signal nature of this
system, the design of the printed circuit board (PCB) layout is critical to maintain the high audio fidelity of BelaSigna 200. To avoid
coupling noise into the audio signal path, keep the digital traces away from the analog traces. To avoid electrical feedback coupling,
isolate the input traces from the output traces.
3.1 Recommended Ground Design Strategy
The ground plane should be partitioned into two: the analog ground plane (AGND) and the digital ground plane (DGND). These two
planes should be connected together at a single point, known as the star point. The star point should be located at the ground terminal
of a capacitor on the output of the power regulator as illustrated in Figure 2.
Figure 2: Schematic of Ground Scheme
The DGND plane is used as the ground return for digital circuits and should be placed under digital circuits.
The AGND plane should be kept as noise-free as possible. It is used as the ground return for analog circuits and it should surround
analog components and pins. It should not be connected to or placed under any noisy circuits such as RF chips, switching supplies or
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