Dummy sizes for matching

[ripoo82]

Is there any rule of thumb for the dummy size in a highly matched MOS array?

From what size you start reducing the dummy size, or is it better to always full size dummies?

 

[erikl]

I've learnt it is important to keep the "environment" as uniformly as possible, i.e. spacings and layers, particularly the poly. So it is enough to have dummies with the same spacing and the same longer side (usually the width), but they don't need to have the dimension of the shorter side (length, then); min. dimension is enough.