Amplify Your Capabilities in Signal Integrity Assessment
In the realm of Printed Circuit Board (PCB) design, the importance of Signal Integrity (SI) analysis cannot be overstated. This technique, when integrated into the design workflow, helps predict and mitigate signal degradation before manufacturing, ensuring reliable and high-performance PCB operation from the earliest design stages.
The process commences with a thorough review of the PCB stackup layers, dielectric constants, and trace widths. Minor variations in these factors can significantly impact impedance, and it's crucial to ensure that trace impedance matches the target values, such as 50 ohms for single-ended or 90 ohms for differential.
Next, the routing topology is analysed to eliminate unnecessary stubs, sharp bends, or vias that may cause reflections or signal loss. Maintaining continuous reference planes under high-speed traces is essential to provide low-inductance return paths and prevent signal degradation.
Simulation plays a pivotal role in this process. Tools like Cadence Sigrity or Sigrity X are employed to simulate critical nets, helping to identify and resolve SI challenges effectively. The channel simulation uses PRBS (pseudo-random binary sequence) to evaluate the signal integrity.
Transient analysis is one of the key aspects to ensure signal integrity in the design. It allows designers to predict performance and identify issues early. The RapidScan function in Keysight EDS can be used to cross-verify the anticipated values.
Signal integrity verification early in the design phase enables the formulation of design rules that guide the layout process, reducing risks of signal degradation, noise, loss, or distortion as designs advance toward manufacturing. Testing prototype waveforms with high-bandwidth oscilloscopes complements simulations.
Moreover, techniques like PCB edge plating further aid SI by reducing EMI and impedance discontinuities at board edges, thereby boosting high-frequency signal quality and reliability.
In summary, the robust signal integrity simulation workflow includes extracting the channel EM model, dissecting channel data, and exploring design space. This multi-step, integrated workflow substantially reduces risk and improves first-time-right design outcomes.
For those interested in learning more about SI analysis, the High-Speed PCB Design Guide offers explanations of signal integrity issues, understanding transmission lines and controlled impedance, selection process of high-speed PCB materials, and high-speed layout guidelines. A webinar is also available, providing practical knowledge of SI analysis, and users can learn more about any particular aspect of signal integrity simulation by commenting in the section.
The impedance calculator, such as those found in technology like Cadence Sigrity or Sigrity X, assists in ensuring that the trace impedance matches the target values, like 50 ohms for single-ended or 90 ohms for differential.
For effective signal integrity analysis, a stackup designer should consider factors like dielectric constants and trace widths, and employ data-and-cloud-computing technologies to streamline the design and simulation process.
