Analog Integrated Circuits and Signal Processing

, Volume 101, Issue 2, pp 219–228 | Cite as

A LNA-merged RF front-end with digitally assisted technique for gain flatness and input-match compensation

  • Xu Yan
  • Yu Li
  • Yang Chen
  • Hao Zhang
  • Zheng Zhong
  • Liguo SunEmail author
  • Fujiang Lin


In this paper, a wideband LNA-merged RF receiver front-end (RFE) with digital assist (DA) for conversion gain flatness and input-match compensation is presented. It employs a novel common gate \(g_m\)-stage with multiple feedback, double-balanced Gilbert-type switches and active loads to form stacking topology. The conversion gain boost factor and input-match compensation factor can be controlled by DA. Theory and simulation results show that DA broaden the RF bandwidth of the proposed RFE and improve the conversion gain flatness. A prototype of the presented RFE is designed and fabricated in the SMIC 40-nm CMOS process, the active area is just \(0.03\,{\hbox {mm}}^2\). From measurement results, the proposed RFE achieves conversion gain of 7.5 dB, 10.0 dB and 12.5 dB from 0.5 to 3.5 GHz with 0.3 dB inband ripple. The best IIP3 is 1.5 dBm. The minimum SSB NF is 11.3 dB. The average DC power is only 3.2 mW from a 1.1 V supply.


RF front-end (RFE) Merged LNA Conversion gain boost Input-match compensation Digital assist (DA) 



This work is supported by the Fundamental Research Funds for the Central Universities, China, under the Project No. WK6030000082. The major work is performed at MESIC (a joint lab of USTC and IMECAS), and partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication. The authors would like to thank the Information Science Laboratory Center of USTC for software and hardware services.


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Xu Yan
    • 1
    • 3
  • Yu Li
    • 1
  • Yang Chen
    • 2
  • Hao Zhang
    • 1
  • Zheng Zhong
    • 3
  • Liguo Sun
    • 2
    Email author
  • Fujiang Lin
    • 1
  1. 1.Micro-/Nano-Electronic System Integration Center (MESIC)University of Science and Technology of China (USTC)HefeiChina
  2. 2.Department of EE and Information Science (EEIS)University of Science and Technology of China (USTC)HefeiChina
  3. 3.Department of Electrical and Computer Engineering (ECE)National University of Singapore (NUS)SingaporeSingapore

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