A 2.4-Ghz Dual-Mode Resizing Power Amplifier With A Constant Conductance Output Matching

A 2.4-GHz dual-mode power amplifier with transistor resizing is proposed. The proposed technique keeps the conductance for optimum power-matching constant in both modes. By introducing transformers and capacitors, the 50-ohm load is matched to near-optimal impedances for size-scaling MOS transistors. Using a 0.18-mu m CMOS process, the proposed PA demonstrates a PAE enhancement of 2.7x/2.3x respectively at 6.5-dB/9-dB transmitting power back-off.