A Quadrature Switched-Capacitor RF-DAC Drain Efficiency Model for Back-Off Operation

In this paper a linear, code-dependent model for drain efficiency estimation of radio-frequency switched-capacitor power amplifiers in back-off operation mode is presented. Given a certain modulation scheme this model provides an estimation for output power and drain efficiency in back-off operation, which enables comparison between different modulation schemes and transmitter (TX) architectures like digital intensive quadrature and polar including hybrid polar-I/Q concepts. The model is validated against circuit simulations for a CMOS 28 nm technology.