PCB Signal Integrity, Power Integrity and EMC Challenges

For PCB and package designs, the issues of crosstalk, reflections, skew, ringing and other classical signal integrity challenges are pervasive and growing. A meaningful assessment of such effects requires system-level consideration to reliably account for coupling among traces as well as planes, vias and other design structures. System-level analysis also enables consideration of power integrity issues, such as power dissipation, thermal issues, current constraints and power plane noise. Distinctions between signal integrity (SI) and AC power integrity (PI) have blurred, and the need for design-side consideration of EMC has escalated. Simultaneous switching noise (SSN) is a perfect example of the coupling between SI effects and the underlying PI root cause. It is often the case, as for DDR memory circuits; this same SSN situation causes excessive power plane emissions and results in EMC issues. Therefore, system-level SI, PI and EMC are much more closely related than most designers realize.