I was very happy to write a post for Altium. Read the full article at the Altium blog here >>
Do you plan ahead when working on CPU DDR3 fanout?
Choosing the correct VIA for a particular memory group and deciding on how PCB layers will be used can make DDR3 layout a lot easier. Assigning different colors to each memory group help visualize the interface.
Why to use uVIAs instead of through hole VIAs for Address, Command and Control signals?
The Address, Command and Control group has the highest number of signals from the memory groups. If we chose through hole VIAs, we would use a lot of space on all the layers. By choosing uVIAs, we only need the space on the Layer 3 and because uVIA is smaller in diameter, we also have more space to fanout the signals on Layer 3.
Read the full article here >>
Welldone Blog 
You use stacked micro-vias then? Am I correct to assume that your next layer from the top would be a ground plane? If it is, you must have to drop down two layers to get so your next signal plane, yes?
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Hi Brad,
– no stacked microvias.
– yes, the L2 is GND. I used L1-L2 and L2-L3 uVIAs connected on the Layer 2 with very short tracks.
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