Signal and power integrity process
Signal integrity (SI) and power integrity (PI) are the key factors in achieving optimum board/system performance and are a main concern in today's high-speed designs. At speeds where the electrical delay exceeds or becomes a significant portion of the signal edge-times, interconnects must be considered as transmission lines with distributed properties, similar to microwave circuits. Transmission lines must be designed to minimize distortion of the signals at the receivers, which are mainly due to:
- Reflections and ringing
- Impedance-discontinuity due to non-ideal current paths
- Shifts in reference-levels (power and ground bounce)
- Switching noise due to currents across impedance of the PCB power distribution system
Therefore, characteristic impedance, impedance matching, propagation delay and timing, crosstalk and current path are critical areas to consider in a design. In addition, the selection of PCB materials, the layer stack design and an ideal assignment of the layers, as well as power decoupling and bypassing are also areas of concern. Often old rules of thumb may no longer work, and the fundamentals of the high-speed electromagnetic (EM) propagation must be understood and applied in design.
As a result, simulation based analysis becomes increasingly key for the correct performance of high-speed printed circuit boards and electronic systems. Our consulting strategy for SI and PI is to focus these analysis techniques on the concept and pre-layout phase or concurrent during placement and routing and not to limit them on post-layout verifications.
Our service provides a wide range of different offerings with regards to signal integrity including:
Design process audits and assessments
A detailed analysis of design processes and the environments with special focus on signal integrity to enable you to find and implement the ideal solutions for optimized high-speed design.
Zuken's engineers can help you in your current high-speed design process – either as additional resource or for getting started with new software in a quick and efficient manner to address the challenges of interconnect design, including the necessary modeling tasks.
Analysis and verification
Signal and power integrity problems often occur late in the design process or when the first prototypes are built or already working. Zuken's high-speed PCB Design consulting provides expertise for post-layout SI/PI analysis on PCBs to detect problems which may not been found without the help of simulation tools. Working with the customer, the problematic areas of the board are analyzed in detail and the results are documented in order to efficiently and effectively solve the problems encountered.
Special attention should be given to the issue of "PCB Power Bus Design and Decoupling Concepts", which includes aspects related to the supply and ground system of a printed circuit board. With higher complexity, integration and performance of the customers' designs, the demands on the power bus design get more critical. A proper power bus design is the basic requirement for good signal integrity and EMI behavior and therefore key for successful high-speed design.