A CMOS Broadband Power Amplifier With a Transformer-Based High-Order Output Matching Network
A transformer-based high-order output matching network is proposed for broadband power amplifier design, which provides optimum load impedance for maximum output power within a wide operating frequency range. A design methodology to convert a canonical bandpass network to the proposed matching configuration is also presented in detail. As a design example, a push-pull deep class-AB PA is implemented with a third-order output network in a standard 90 nm CMOS process. The leakage inductances of the on-chip 2:1 transformer are absorbed into the output matching to realize the third-order network with only two inductor footprints for area conservation. The amplifier achieves a 3 dB bandwidth from 5.2 to 13 GHz with +25.2 dBm peak P_sat and 21.6% peak PAE. The EVM for QPSK and 16-QAM signals both with 5 Msample/s are below 3.6% and 5.9% at the output 1 dB compression point. This verifies the PA's capability of amplifying a narrowband modulated signal whose center-tone can be programmed across a large frequency range. The measured BER for transmitting a truly broadband PRBS signal up to 7.5 Gb/s is less than 10^(-13) , demonstrating the PA's support for an instantaneous wide operation bandwidth.
© 2010 IEEE. Manuscript received April 27, 2010; revised August 11, 2010; accepted August 12, 2010. Date of current version December 03, 2010. This paper was approved by Guest Editor Kari Halonen. The authors would like to thank Prof. A. Emami and Dr. S. Weinreb at Caltech for their technical advice. The authors also acknowledge Mr. Ta-Shun Chu at USC, Prof. Y. J. Wang at NCTU, Mr. S. Kousai at Toshiba, the members of Caltech CHIC group for their numerous suggestions, and Toshiba Corporation for chip fabrication.
Published - Wang2010p12333Ieee_J_Solid-St_Circ.pdf