A 65-nm CMOS Wideband TDD Front-End With Integrated T/R Switching via PA Re-Use

作者：Xiao Xiao^*; Pratt Amanda; Yang Bonjern; Wang Angie; Niknejad Ali M; Alon Elad; Nikolic Borivoje

来源：IEEE Journal of Solid-State Circuits, 2017, 52(7): 1768-1782.

DOI：10.1109/JSSC.2017.2702669

• Low-noise amplifier
• PA re-use
• polar transmitter
• power amplifier
• T/R switch
• TDD front-end
• transformer

Time-division duplex (TDD) systems rely on offchip transmit/receive (T/R) switches to isolate the RX from the high-output power of the TX, while existing on-chip T/R switching solutions are narrow-band or high loss. This paper presents a wideband integrated T/R switching technique that eliminates the conventional, lossy series T/R switch from the signal path. The system reconfigures the PA as an LNA during the receive mode, and utilizes only DC mode control switches to enable TDD co-existence. To demonstrate this technique, a polar transmitter that can be re-purposed into a common-gate LNA is implemented in 65-nm CMOS. With an integrated front-end balun transformer, the transmitter achieves 20-dBm peak output power with 32.7% peak drain efficiency. In the receive mode, the PA is reconfigured into a wideband 3.4-5.4-GHz LNA achieving -6.7-dBm P1dB, and 5.1-dB noise figure.

• 出版日期2017-7