Issue link: https://iconnect007.uberflip.com/i/1489778
14 DESIGN007 MAGAZINE I JANUARY 2023 top layer to sig 2, the first internal signal layer, top-plane 1, plane 1-plane 2, plane 2-signal 2. is is due to a need for planes to act as shields between pairs of signal layers and the need for planes to be added as pairs to form planar capacitance to handle the high-speed switch- ing current demand of the digital circuits. Regarding some of the signal integrity issues that might be encountered using this technique, we will look at two adjacent signal layers— a dual stripline structure (Figure 10). First, you will notice parallelism between the traces Figure 7: Screen shot of another step in the sequence. Figure 9: Escape routing screen shot illustrates the complexity of BGA routing today. Figure 10: Two adjacent signal layers—a dual stripline structure. Figure 8: Escape routing sequence, continued.