Articles by Lee Ritchey

The expansion of the resin systems in laminates has been a source of reliability problems as the electronics industry has placed ever higher demands on those used in printed circuit boards. Suppliers of these resin systems have improved their resin systems to eliminate or minimize failures from expansion as the systems using the PCBs have been made more complex and subjected to ever harsher environments. Currently, the only technologies that still suffer failures from resin expansion with temperature are triple-high stacked blind vias, which Lee Ritchey explores in this article.

Within the PCB industry, FR-4 materials have long been accepted as “standard” materials. However, their use was not specific to the types of board being designed. For today’s high-speed, high-frequency designs, careful engineering and material selection relative to the resin systems and glass weave styles needed will ensure that a product will work as specified, as designed, and as manufactured. In addition, the finish of the copper used in the signal and power layers also needs to be controlled in order to ensure that loss goals are met.

Successfully designing a PCB with more than one impedance while maintaining a manufacturable and economical product can be a difficult challenge. By examining the histories and uses of various impedances, Lee Ritchey simplifies the process and discusses the ideal impedance for PCB stackup design.