Power and signal integrity of printed circuit boards

Abstract

Abstract Printed circuit board (PCB) design is a complex process with small tolerances. A single fault could cause a malfunction of the complete system, requiring a costly redesign to regain a functional product. Introducing simulation tools in the design process could help identify problems with the PCB early in the design, reducing the need for physical prototypes, thus saving cost and reducing the environmental impact. This thesis investigates how different layouts affect the performance of the PCB in three key areas, including thermal behavior, power integrity (PI) and signal integrity (SI). Different design options were evaluated using simulations, which were later compared to measurements on physical boards. The simulated temperature and voltage drop of the PCB matched well with the measured values. In comparison, the impedance simulations had greater deviations from the measured values, where the differences were greater for power delivery networks compared to transmission lines. However, the impedance simulations of alternative designs gave a good visualization of the differences between the designs, which agreed with the general differences captured by the measurements. Some scenarios, including close decoupling placement and far-end crosstalk, were harder for the simulation to accurately predict. While stripline transmission lines and near-end crosstalk were easier to simulate. Changing the design of copper interconnects in the layout played a big role in deciding the final performance of the PCB, concerning thermal behavior, PI and SI. Utilizing simulation software in the design process allows for a good comparison between design alternatives, without the need to order a prototype. However, exact values of a certain design could be harder for the simulation to accurately estimate.