I=92m designing an eight Layer PCB Board that has LVDS signals in frequency of 700Mbps. I have read lots of Document regarding Impedance Controlled PCB routing. The desired impedance is 100 Ohm as I read the device datasheet. But in some Application note I=92ve seen that the Impedance should be 75 ohm or 85 ohm. For example as I see in (part of
2.2.1)As you see the track width is differs by 4mil in top layer relative to mid-layers. How can I change the Stackup that the track width be closer to each other in different layers? Is there software that helps me or a site that has some example of stackup?( I know that the HyperLynx can do this but I don=92t have much time to learn it and I=92m looking for other ways in the little time that I have.)