Overview

Both add-in card and ExpressCard topologies allow system designers to create new and exciting opportunities for the use of PCI Express technology. In many instances, the interconnect design requirements for add-in cards and ExpressCard modules simply require you to extend or borrow from the system-level guidelines presented elsewhere in this book.

This chapter addresses additional design criteria that are specific to add-in cards and ExpressCard modules. In addition to the information presented here, you should understand the system-level design implications for supporting an ExpressCard or add-in card slot, as discussed in Chapter 5, "Successful System Layout Design."

Note that while ExpressCard modules are defined to include both Universal Serial Bus (USB) and PCI Express interconnects, this chapter discusses only the PCI Express aspects of the interconnect.

Form Factor Requirements

Both add-in cards and ExpressCard modules have form factor and mechanical provisions that help to ensure a broad range of compatibility. As a card or module designer, understanding these requirements can help you to achieve optimum interconnect performance for your PCI Express signals. As a system designer, understanding the card and module form factor specification will help you have a fully compatible and functional system.

Exact mechanical specifications and chassis or container details are beyond the scope of this chapter and book. As always, you should obtain all necessary mechanical and chassis requirements from the appropriate specifications.