  In this paper, various Miller-compensated amplifiers are analyzed by using
the two-port feedback analysis together with the root-locus diagram. The
proposed analysis solves problems of Miller theorem/approximation that fail to
predict a pole-splitting and that require an impractical assumption that an
initial lower frequency pole before connecting a Miller capacitor in a
two-stage amplifier should be associated with the input of the amplifier. Since
the proposed analysis sheds light on how the closed-loop poles originate from
the open-loop poles in the s-plane, it allows the association of the
closed-loop poles with the circuit components and thus provides a design
insight for frequency compensation. The circuits analyzed are two-stage
Miller-compensated amplifiers with and without a current buffer and a
three-stage nested Miller-compensated amplifier.
