PCB Why Avoid Right-Angle Routing? Three Compelling Reasons!
PCB Why Avoid Right-Angle Routing? Three Compelling Reasons!
In the realm of electronic engineering, the Printed Circuit Board (PCB) is a fundamental component that serves as the backbone of any electronic device. From smartphones to computers, from medical equipment to aerospace systems, PCBs are integral to the functionality of these devices. However, one of the most crucial aspects of PCB design that often gets overlooked is the routing of traces or wires. Specifically, the avoidance of right-angle routing, which can significantly impact the performance, reliability, and even the longevity of a PCB. This article explores three compelling reasons why PCB designers should steer clear of right-angle routing.
Reason One: Electromagnetic Interference (EMI)
Electromagnetic interference (EMI) is a significant concern in PCB design. EMI refers to the unintended emission of electromagnetic energy from a device or system that can interfere with the operation of another device. In the case of PCBs, right-angle routing can exacerbate this issue. When traces make sharp turns, they create localized areas of high electric field concentration. These concentrated electric fields can emit electromagnetic radiation, especially at higher frequencies. This radiation can interfere with nearby components, disrupting their operation and potentially causing failures.
Moreover, right-angle routing can also increase the susceptibility of a PCB to external EMI. The sharp corners created by right-angle routing act as antennae, amplifying and concentrating incoming electromagnetic waves. This increased sensitivity to external EMI can lead to signal degradation, noise pickup, and even damage to sensitive components.
By avoiding right-angle routing and instead using rounded or curved traces, PCB designers can significantly reduce the risk of EMI. Rounded traces distribute the electric field more evenly, minimizing localized areas of high concentration. This not only reduces the emission of EMI but also decreases the susceptibility of the PCB to external interference.
Reason Two: Mechanical Stress and Reliability
Mechanical stress is another crucial consideration in PCB design. The traces on a PCB are subject to various forces, including thermal expansion and contraction, vibration, and even accidental impact. Right-angle routing can exacerbate these stresses, leading to reliability issues and even premature failure of the PCB.
When traces make sharp turns, they create stress concentrations at the corners. These concentrated stresses can cause trace cracks or even complete breaks over time. The severity of this issue increases with the number of right-angle turns on a PCB. As a result, boards with excessive right-angle routing are more likely to experience reliability issues, such as intermittent failures or complete breakdowns.
In contrast, rounded or curved traces distribute mechanical stress more evenly along the length of the trace. This reduces the likelihood of stress concentrations and associated failures. Additionally, curved traces are better able to withstand thermal expansion and contraction, as they can flex and conform to the changing dimensions of the PCB.
Reason Three: Signal Integrity and Performance
The final reason for avoiding right-angle routing on PCBs relates to signal integrity and overall performance. Sharp corners created by right-angle routing can introduce impedance discontinuities into the traces. These discontinuities can cause signal reflections, distortions, and even losses. As a result, signals transmitted through traces with right-angle turns are more likely to arrive at their destination distorted or weakened.
Impedance discontinuities are particularly problematic for high-frequency signals. At higher frequencies, the wavelength of the signal becomes shorter, and even small variations in impedance can have significant effects. Right-angle routing can introduce significant impedance discontinuities, degrading the performance of high-speed circuits and potentially limiting the bandwidth of the PCB.
By using rounded or curved traces, PCB designers can minimize impedance discontinuities and preserve signal integrity. Rounded traces provide a smoother transition in impedance, reducing the likelihood of signal reflections and distortions. This not only improves the performance of high-speed circuits but also ensures that signals arrive at their destination accurately and with minimal loss.
Conclusion
In conclusion, avoiding right-angle routing on PCBs is crucial for ensuring optimal performance, reliability, and longevity. Right-angle routing can exacerbate issues such as electromagnetic interference, mechanical stress, and signal integrity degradation. By using rounded or curved traces instead, PCB designers can minimize these risks and create more robust and reliable boards. As technology continues to advance and the demand for higher-performance electronics increases, the importance of avoiding right-angle routing on PCBs becomes even more apparent.
