Proper stackup design is important because it forms the basis of a successful printed circuit board (PCB) design. Newer ICs today have edge rates in the sub-nanosecond range; the fastest of which are multi-gigabit transceivers that have edge rates of less than 100ps. With such fast edge rates, it is important to tightly control trace impedance to meet signal integrity requirements and have consistent reference planes to meet our electromagnetic compatibility requirements. It is also essential that we explore stackup options so as not to compromise board yields as well as add unnecessary cost to the manufacturing process.