How to Ensure Signal Integrity in Complex Printed Circuit Board Assembly
Complex Printed Circuit Board Assembly
In high-speed electronic systems, signal integrity is critical to maintain reliable communication between components. However, the higher the speed of signals, the more they’re susceptible to interference from internal and external sources. The fidelity of these signals is degraded by crosstalk, impedance mis-matches, ringing, ground bounce and other problems that manifest as transmission errors that can cause devices to malfunction or fail altogether.
How do you ensure signal integrity in a complex printed circuit board assembly? The answer lies in careful PCB layout and the use of design tools that can simulate and predict performance at a given level of detail. This includes SPICE simulators, Laplace and Fourier analysis, and other signal-related calculations, such as conversions between time-domain data and frequency-domain data (S-parameters).
The process of ensuring good signal integrity in a PCB starts with the development of an appropriate set of layout rules. These will govern trace width and spacing for different types of signals, differential pairs and other high-speed topologies, and different power and ground requirements. They will also control the routing layers and the routing direction on those layers, and they may even specify special areas where necking down the traces is necessary, such as within BGAs.
How to Ensure Signal Integrity in Complex Printed Circuit Board Assembly
Next comes the task of choosing the right laminate and stack-up to optimize signal integrity. This will require an understanding of the dielectric loss tangent of the selected laminate and how that affects impedance matching. It will also involve selecting a layer stack-up that minimizes the number of blockages on the reference plane, as these can increase noise on high-speed signals as they wander around looking for a clear path back to their source.
Finally, it is vital to ensure that there is adequate space for routing the sensitive signals on a PCB. This requires careful planning of escape routing, and ensuring that the signals are not routed through areas where they might get overloaded with noise from other high-speed signals or the power supply. It is also essential to avoid any routing that might take signals through dense areas of the board that could add unwanted coupling between the traces and other components.
A PCB that has been designed with these principles in mind will provide the best possible communication between electronic components. This will result in the reliable operation of a system without excessive transmission errors, and will also protect against damage from electromagnetic interference. For a comprehensive approach to signal integrity, it is important to work with a PCB manufacturer that provides a wide range of services, including prototyping, engineering and manufacturing services.
This way, any issues that might arise during a prototype can be addressed before production begins and the problem doesn’t slip through to the finished product. Altest is a leader in this field and can offer both of these services, as well as a range of other value-added services, such as design assistance, component procurement, warehousing, and RMA support staff. Contact us today to learn more.