[SOLVED] What is the difference between the two common centroid structures?

[goatmxj666]

Hello
I am studying about differential pair layout.
The gate signal crosses the first common centroid structure, and the drain signal crosses the second common centroid structure.
I am wondering what are the pros and cons of both structures.

 

[kemiyun]

It really depends on what you're trying to do, there isn't a single solution to rule them all.

In both of these drawings signals cross each other. The difference is which group of signals are coupling more to the tail node, gates or drains and which signal is routed longer which may expose it to other coupling. Either one could pass depending on application and optimization.