A +32 dBm 1.85 GHz class-D outphasing RF PA in 130nm CMOS for WCDMA/LTE

This paper presents a Class-D outphasing RF Power Amplifier (PA) which can operate at a 5.5V supply and deliver +32dBm at 1.85 GHz in a standard 130nm CMOS technology. The PA utilizes four on-chip transformers to combine the outputs of eight Class-D stages. The Class-D stages utilize a cascode configuration, driven by an AC-coupled low-voltage driver, to allow a 5.5 V supply in the 1.2/2.5 V 130nm process without excessive device voltage stress. Spectral and modulation requirements were met when a WCDMA and an LTE signal (20 MHz, 16-QAM) were applied to the outphasing PA. At +28.0 dBm channel power for the WCDMA signal, the measured ACLR at 5 MHz and 10 MHz offset were −38.7 dBc and −47.0 dBc, respectively. At +24.9 dBm channel power for the LTE signal, the measured ACLR at 20MHz offset was −34.9 dBc. To the authors' best knowledge, the PA presented in this work has a 3.9 dB higher output power compared to published CMOS Class-D RF PAs.

[1]  Jeffrey S. Walling,et al.  A switched-capacitor power amplifier for EER/polar transmitters , 2011, 2011 IEEE International Solid-State Circuits Conference.

[2]  Ali Hajimiri,et al.  Distributed active transformer-a new power-combining and impedance-transformation technique , 2002 .

[3]  J.S. Yuan,et al.  MOS RF reliability subject to dynamic voltage stress-modeling and analysis , 2005, IEEE Transactions on Electron Devices.

[4]  M. Ruberto,et al.  A reliability-aware RF power amplifier design for CMOS radio chip integration , 2008, 2008 IEEE International Reliability Physics Symposium.

[5]  John R. Long,et al.  A 58–65 GHz Neutralized CMOS Power Amplifier With PAE Above 10% at 1-V Supply , 2010, IEEE Journal of Solid-State Circuits.

[6]  Yorgos Palaskas,et al.  A highly linear 25dBm outphasing power amplifier in 32nm CMOS for WLAN application , 2010, 2010 Proceedings of ESSCIRC.

[7]  K. Soumyanath,et al.  A 28.1dBm class-D outphasing power amplifier in 45nm LP digital CMOS , 2009, 2009 Symposium on VLSI Circuits.

[8]  J.R. Long,et al.  Monolithic transformers for silicon RF IC design , 2000, IEEE Journal of Solid-State Circuits.

[9]  Wim Dehaene,et al.  A high-voltage output driver in a 2.5-V 0.25-μm CMOS technology , 2005 .

[10]  Gang Liu,et al.  Fully Integrated CMOS Power Amplifier With Efficiency Enhancement at Power Back-Off , 2008, IEEE Journal of Solid-State Circuits.

[11]  J.S. Yuan,et al.  Evaluation of RF-Stress Effect on Class-E MOS Power-Amplifier Efficiency , 2008, IEEE Transactions on Electron Devices.

[12]  W. Dehaene,et al.  A high-voltage output driver in a 2.5-V 0.25-/spl mu/m CMOS technology , 2005, IEEE Journal of Solid-State Circuits.

[13]  F. Svelto,et al.  Oxide Breakdown After RF Stress: Experimental Analysis and Effects on Power Amplifier Operation , 2006, 2006 IEEE International Reliability Physics Symposium Proceedings.

[14]  Sungho Lee,et al.  A CMOS Outphasing Power Amplifier With Integrated Single-Ended Chireix Combiner , 2010, IEEE Transactions on Circuits and Systems II: Express Briefs.

[15]  J.R. Long,et al.  Shielded passive devices for silicon-based monolithic microwave and millimeter-wave integrated circuits , 2006, IEEE Journal of Solid-State Circuits.