A MODIFIED CASCODE AMPLIFIER

摘要

An input signal to an amplifier is coupled to a gate electrode of a first PMOS transistor operating as a common source inverting amplifier. The drain electrode of the first transistor is coupled to the source electrode of a second PMOS transistor via a junction terminal. An output signal is developed at the drain electrode of the second transistor. The junction terminal is coupled to a gate electrode of a third PMOS transistor, operating as a common source inverting amplifier. The drain electrode of the third transistor is coupled to the gate electrode of the second transistor for maintaining the drain voltage of the first transistor substantially constant when the input signal changes that maintains the output impedance at the drain electrode of the second transistor high.