A 21-dBm $I/Q$ Digital Transmitter Using Stacked Output Stage in 28-nm Bulk CMOS Technology

This paper proposes the use of a high-power stacked output stage for a current-based in-phase/quadrature (I/Q) direct digital to RF modulator (DDRM) in bulk CMOS. The main nonlinearities associated with implementing the stacked transistor on top of the I/Q DDRM are easily compensated by a simple 2-D digital predistortion. A prototype implemented in 28-nm bulk CMOS achieves a saturated output power...