Digital RF transmitter architectures exploiting FIRDACs in various configurations

This paper discusses various ways to take advantage of semi-digital FIR filters (or FIRDACs) in highly digital RF and millimeter-wave transmitters. FIRDACs combine in a single block digital-to-analog conversion and filtering. When fed with 1-bit digital signals provided by digital delta-sigma modulators or other sources, the inherent linearity of 1 bit D-to-A converters is also preserved reducing significantly the sensitivity to component matching. Architectures using FIRDACs in base-band, IF or RF sections will be discussed, as well as opportunities for reconfiguration in highly advanced CMOS processes. Implementation examples in advanced technologies down to 28nm CMOS demonstrate the performance and scalability of these architectures.