Patent ID: 6570450
Filing Date: 2003-05-27
Classification: H03F

Abstract:
A CMOS transistor amplifier for amplifying a small RF signal in Class AB operating mode comprising:a) a first P channel transistor serially connected with a first N channel transistor, each of the first transistors having a gate terminal for controlling the conduction of the transistor, b) a first bias circuit for applying a first DC bias voltage to the gate of the first P channel transistor, the first bias circuit comprising a second P channel transistor serially connected with a first current source, the first bias voltage being taken at the gate and drain of the second P channel transistor and a second bias circuit for applying a second DC bias voltage to the gate of the first N channel transistor, the second bias circuit comprising a second N channel transistor serially connected with a second current source, the second bias voltage being taken at the gate/drain of the second N channel transistor, wherein the first DC bias voltage is applied through a first resistor to the gate of the first P channel transistor, and the second DC bias voltage is applied through a second resistor to the gate of the first N channel transistor, c) an input circuit for capacitively coupling a small RF input signal to the gate of the first P channel transistor and to the gate of the first N channel transistor, and d) an output circuit connected to a common terminal of the serially connected first transistors.