27:22 I think the reason impedance here (output impedance?) is directly from PMOS SSM, rather than from "hand analysis simplified" model? 28:56 How that is a Common Drain? 30:48 How can you do top and bottom analysis separately instead of treating the whole circuit as a whole, like you did in 10:05? 31:59 I thought you said on 31:37 it's a CG not a CD? Why are we looking at a CD?