Analysis and implementation of derivative superposition for a power amplifier driver

A new expression is proposed to analyze the linearization effectiveness of derivative superposition(DS) with large and small signal inputs,and different optimization methods of DS are found for different input magnitudes. A power amplifier driver(PAD) with large-signal optimized DS was implemented in 0.13μm technology within a reconfigurable RF transmitter.The PAD is compatible with the GSM band at 900 MHz and the WCDMA band at 1.95 GHz,and it has a gain range of 44 dB with a step of 2 dB.Measurement results show that the overall OIP3 of the transmitter is better than 19 dBm,and the output referred 1-dB compression point is better than 7.5 dBm.