Linearization methods of RF CMOS PAs for mobile communications

Although a CMOS device has inferior characteristics for PA it allows versatile controls and possible integrations with other circuits. These advantages surely provide us various methods to linearize a PA with resultant high efficiency. Several linearization methods of RF CMOS PAs are introduced in this paper. These are mostly based on adaptively controlling the biases of common source and common gate power transistors with the input envelope in many different manners. The other type effort is shown for a power driver linearizer which is made of a digital vector modulator. As examples, RF CMOS PAs for WCDMA and WLAN are demonstrated.