5. Add stitching vias:
a. Select the via structure menu option to add via structures
b. Set parameters for via spacing (e.g., every 500 mils)
These are some of the most important options for getting your PCB placed, routing and ready for manufacturing. Now let's
take a look at constraints for high-speed PCBs.
Constraints for Signal Integrity
Advanced constraints include rules for high-speed complex printed circuit boards. Standard PCBs are usually 300 compo-
nents or fewer, where the primary concern is designing for manufacturing, fabrication, assembly, and test, then maybe differ-
ential pairs and single-ended impedances depending on the protocols in your design.
Complex high-speed PCBs however need considerations for impedance control, differential pairs, inter-pair and intra-pair
skew, a limit on the number of vias and other such factors that manage signal integrity and electromagnetic interference.
Advanced Constraints also account for typical high-density interconnect boards, military grade PCBs and rigid-flex or flex
PCBs. Anything outside the normal DFM considerations would be considered advanced constraints for a printed circuit board.
Now that we understand the difference between regular and advanced constraints, let's look at ways to turn on or off the
kinds of constraints we should enforce in the Constraint Modes section.
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OrCAD X High-Speed Digital Design Guide
