Ultra-Low Power Direct-Conversion 16 QAM Transmitter Based on Doherty Power Amplifier

This letter presents a fully-integrated umW,ltra-low power (ULP) direct-conversion transmitter. For an ULP modulation, a voltage-driven passive-mixer is optimized with a super source follower (SSF) having a low-output impedance. Also, a linear Doherty PA is proposed for a good back-off efficiency. For transmitting a 16-QAM signal with PAPR of 7.5 dB, the efficiency of the Doherty PA is 14% with th...