problem in common centroid matching

[Yathin P U]

Hi all,

I am trying to do the common centroid matching for transistors in the diff. pair (each transistor has W=12u, L=3u, Multipliers = 12). What is the better common centroid matching?

A B B A A B B A
B A A B B A A B
A B B A A B B A

OR

A B A B A B
B A B A B A
A B A B A B
B A B A B A

 

[erikl]

Both are good. I'd leave the decision to the aspect ratio which is best appropriate to fit into the cell design. The 8x3 array will achieve an aspect ratio closer to a square form (vertical gates), which rather supports best matching.

Don't forget (part) dummies around.

 

[jirika]

I agree with erikl. It's usually better to do the first one matching case over the second one (better ABBA then ABAB).

 

[kenambo]

I think first one is better... because the variations are less and it gives better post extraction results...