Efficient Digital Quadrature Transmitter Based on IQ Cell Sharing

In this paper, we proposed and designed a digitally configured versatile RF quadrature transmitter. The transmitter efficiency was enhanced by IQ cell sharing and the deactivation of cells of opposite phases. In simulation, these techniques were able to increase the average efficiency of the transmitter from 46.3% to 70.7% for a 6.9-dB PAPR LTE signal. Moreover, the number of power amplifying cells was halved, improving the total efficiency of the transmitter. The proposed transmitter was implemented in a 6-b configuration at 0.8 GHz using a 28-nm CMOS process. Furthermore, the performance of the transmitter was verified. The dynamic range of the measured output power was in the range -20.2 to 13.9 dBm, and the measured average output power was 6.97 dBm for the 6.9-dB PAPR LTE signal. The measured power-added efficiencies of the transmitter at the peak power and average power were 40.43% and 29.1%, respectively.