One effective method is to partition the circuit board according to modules, and create clear quiet zones between the partitions to reduce the impact of power supply and ground on the signal, thereby minimizing noise. Let’s analyze and address these specific methods together.
When examining a high-performance circuit board, its overall distribution should be immediately apparent (assuming we know the intended function of the board). This principle aligns with the concept of separating functional modules. A functional module consists of circuits that are combined with electronic components to achieve a specific function. In practical design, it is important to place these electronic components in close proximity to reduce wiring length and optimize the functionality of the circuit module. This concept is easily demonstrated in the design of common development boards and mobile phones, where modules are separated and shielded using Faraday cages to minimize noise.
The above picture shows a PCB of a development board. The layout clearly separates each interface circuit, ensuring no mutual interference between the wiring of SDRAM, DDR, and SD card interface circuits. Partitioning the system modules helps maintain signal integrity, prevents high-frequency interference, and improves system stability.
When analog and digital circuits coexist on a circuit board, it is crucial to separate them. A “quiet zone” physically separates these circuits or modules to prevent interference. In cases where space constraints limit the creation of a quiet zone, alternative design approaches can be considered.
A. Use transformers or signal isolation components to create circuit separation.
B. Implement filter circuits to prevent ESD and eliminate noise.
C. Utilize common mode inductors for signal protection and stability.
Ditch protection is a technique where the copper skin in the quiet zone is removed, creating a bare circuit board material. However, care must be taken when wiring passes through these protected trenches to avoid RF loop currents that can affect circuit performance.
Devices like ADC and DAC components often connect ground parts internally. These components should be separated into standard reference grounds to prevent noise generation. Devices with separate AGND and DGND pins can simplify circuit design.
If noise is detected on the circuit board, troubleshooting methods should be applied before considering a redesign. WellCircuits Limited specializes in manufacturing high-precision circuit boards tailored to various product needs, including double-sided, multilayer, impedance-controlled, and specialized circuit boards.
