High-Speed, Chip-to-Chip Interconnections Using Flex Circuit Technology - An Update

摘要

Alittle over three years ago, this column first described thernconcept of segregating the high-speed interconnections of an IC from power, ground, and control and suggested routing those high-speed signals directly from the top iof one IC package to the top of another by means of a controlled impedance flex circuit cable. Power, ground, control, and low-speed signals would continue to be interconnected in the standard manner. It is a concept that garnered some interest early on but traditional solutions were still the mainstay approach. Today, however, the idea has clearly been enjoying much greater interest and has been the subject of some interesting research in recent months. The reasons for the interest are little changed from those described in that earlier column. In essence, high-speed signals are unique. They need special care above and beyond other circuit signals. High-speed interconnection paths made with a printed circuit board are subject to a host of intrinsic problems, such as crosstalk, material variation, sharp circuit directional changes, and a range of parasitic effects.