A Digital Power Amplifier in 28 nm CMOS for LTE Applications

This book shows the development of a power amplifier for LTE at the edge of planar CMOS technology. It includes theoretical design concepts, simulations and measurements for a power amplifier based on uplink specifications for mobile communication defined by 3GPP. It proofs the basic capability of CMOS technology for a full integration on a SoC.
Different power amplifier classes and linearization concepts are summarized and compared. A special focus is given on a selection of published watt-level power amplifiers as well as implemented DPAs. These basic considerations were the foundation for the later implemented designs.
A stand-alone linear power amplifier was developed and characterized as a bare bumped die on a PCB. The DPA was integrated into an LTE transceiver what gave the possibility of on-chip verification of the entire system.
Die pictures of the linear PA and the DPA show their architectures, which are implemented on-chip in 28nm CMOS technology, from the top metal layer perspective.