Common Centroid vs. Fully Symmetric

[Eman Salah El-Din]

I was wondering which one of the following layout styles is better for a differential pair carrying a high frequency signal and for current mirrors:

a) 2D Common Centroid layout
b) 2D Fully Symmetric layout

Thanks in advance,

 

[Junus2012]

I am not sure, but I think the Common Centroid layout is better

 

[erikl]

a) 2D Common Centroid layout - if you understand it correctly:

concerning the devices themselves, Common Centroid means point symmetry,
however
concerning the interior of the devices, it does not mean point symmetry, but mirror symmetry not only concerning the horizontal axis, but also respective to the vertical axis. I call it repeating symmetry: sources/drains always on the same side, current flow always in the same direction.

 

[Eman Salah El-Din]

a) 2D Common Centroid layout - if you understand it correctly:

concerning the devices themselves, Common Centroid means point symmetry,
however
concerning the interior of the devices, it does not mean point symmetry, but mirror symmetry not only concerning the horizontal axis, but also respective to the vertical axis. I call it repeating symmetry: sources/drains always on the same side, current flow always in the same direction.

Fine, thank you

I thought about CC, too, but I wasn't so sure since I am new to this.