A Broadband Mixed-Signal CMOS Power Amplifier With a Hybrid Class-G Doherty Efficiency Enhancement Technique

作者：Hu Song^*; Kousai Shouhei^*; Wang Hua^*

来源：IEEE Journal of Solid-State Circuits, 2016, 51(3): 598-613.

DOI：10.1109/JSSC.2015.2508023

• Broadband
• Class-G
• CMOS integrated circuits
• Doherty power amplifier (PA)
• efficiency
• hybrid
• linearity
• mixed signal
• polar modulation
• reconfigurable

This paper presents a broadband mixed-signal CMOS power amplifier (PA) with a hybrid Class-G Doherty architecture for PA efficiency enhancement up to the deep power back-off (PBO) region. Our proposed mixed-signal linearization technique ensures the PA's amplitude modulation (AM)-AM linearity by digital PA operation and suppresses the PA's AM-phase modulation (PM) nonlinearity by real-time analog phase compensation. The PA is fully integrated in a standard 65 nm bulk CMOS process, and achieves a peak output power (P-out) of +26.7 dBm with a 40.2% peak drain efficiency (DE) at 3.71 GHz. The DE at 6 and 12 dB PBO is 1.8x and 2.6x over the reference Class-B PA operation, advancing the state-of-the-art CMOS PA PBO efficiency performance. The PA 1 dB bandwidth is extended from 1.08 to 1.8 GHz by reconfiguring the phase difference between the main and auxiliary paths in the Doherty PA. In the modulation measurements with 1 MSym/s 16 QAM signals, the PA performs dynamic hybrid Class-G Doherty operation and achieves +20.8 dBm peak P-out with 28.8% DE at 3.71 GHz and 2.42x efficiency enhancement at 8.1 dB PBO over Class-B operation. The real-time AM-PM linearization technique achieves 3.3 and 2.9 dB improvements on the EVM and adjacent channel leakage ratio (ACLR), respectively. The broadband Class-G Doherty operation is also demonstrated with modulated signals.

• 出版日期2016-3