A 16nm, +28dBm Dual-Band All-Digital Polar Transmitter Based on 4-core Digital PA for Wi-Fi6E Applications
Bassam Khamaisi, David Ben-Haim, Anna Nazimov, Assaf Ben-Bassat, Shahar Gross, N. Shay, G. Asa, V. Spector, Yishai Eilat, Ali Azam, Eli Borokhovich, I. Shternberg, Phillip Skliar, Elad Solomon, A. Beidas, T. A. Hazira, A.A. Lane, Eyal Shaviv, G. Nudelman, E. Dahan, M. S. Shemer, Nahum Kimiagarov, Ashoke Ravi, Ofir Degani
Abstract
Due to the ever-growing demand for higher throughput and longer range from portable devices, wireless transmitters (TX) are required to support wider signal bandwidths and deliver elevated output power, while maintaining high efficiency, especially at power back-off (BO). Recently, digital transmitters (DTXs) that feature arrays of controlled digital-PA (DPA) cells have become increasingly popular, since they directly benefit from nanoscale CMOS technology, yielding reduced die area and highly efficient operation [1]–[4]. However, the lower supply voltages of advanced CMOS nodes present challenges in achieving higher output power with good efficiency. In addition, for cost- and system-complexity reasons, it is very desirable to operate a DTX with a single supply voltage, and, to this end, multicore DPAs with 2- and 4-cores have been reported [4]–[7]. Nevertheless, as more advanced nodes are used, the high output power poses reliability challenges to the circuits. [4] has reported a digital-to-time-converter (DTC)-based polar DTX topology that can support wide bandwidths (up to 160MHz) for dual band WiFi6 applications in 28nm planar CMOS. In comparison, this work presents a DPA that delivers high output power (P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</inf> of ~2SdBm), adds support for the new frequency bands of WiFi6E (6 to 7GHz), and presents a reliability-aware circuit topology to address the challenges of an implementation in the more advanced 16nm FinFET process node.