R R 哉>"心 o)0 G T+ TH R A MYTH ≈ R,+R TX vp R =Vn+=(1+)n T+ R TH 2 O VDD DD2 1 2 1 2 (1 ) A TH T I T TH R VV V R R R VV V R + = + ⇓ = ≈ + = + T VTH V + 0