A 375 mW Multimode DAC-Based Transmitter With 2.2 GHz Signal Bandwidth and In-Band IM3 ${< } {-}$ 58 dBc in 40 nm CMOS

A 40 nm CMOS digital-to-analog converter (DAC) based multimode transmitter (MMTX) is presented. The transmitter can be operated in either narrow- or wideband applications. It has a maximum 2.2 GHz signal bandwidth and exhibits an in-band IM3 of less than - 58 dBc. The MMTX consists of a current-steering DAC with digital sinc equalization and rolloff compensation. By implementing high-speed, feed-forward pipelined digital logic and a distributed decoder, the DAC sampling rate extends to 5 GHz. A distributed regulator approach ensures preservation of the achieved wideband linearity in noisy embedded SoC environments. The MMTX can deliver up to +11 dBm of output power and exhibits 20 dB of analog power backoff with 1 dB steps and a precision better than ±0.1 dB. The MMTX consumes only 375 mW and occupies 1.65 mm².