IEEE Journal of Solid-State Circuits · 2017 · 20 citations · 21 references
EngineeringElectrical EngineeringAnalog ElectronicsMicroelectronicsMicrowave EngineeringCmos Circuit DesignHigh-frequency Semiconductor DevicesMicrowave Integrated CircuitsMixed-signal Integrated Circuit DesignRadio-frequency Integrated CircuitsSwitching TechniquesCmos Analog Integrated CircuitsCmos Radio-frequency CircuitsNoise FigurePower OutputRadio-frequency Integrated Circuit DesignReconfigurable Rf Front EndsRf Cmos DesignTransmitter Design
Time-division duplex (TDD) systems rely on off-chip 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.
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