CMOS Distributed Amplifiers Using Gate-Drain Transformer Feedback Technique

• Published in: IEEE transactions on microwave theory and techniques 2013-08, Vol.61 (8), p.2901-2910
• Main Authors: Chih-Yin Hsiao, Tzu-Yu Su, Hsu, Shawn S. H.
• Format: Article
• Language: English
• Subjects: Amplifiers; Applied sciences; Bandwidth; Circuit properties; CMOS; CMOS integrated circuits; CMOS technology; Couplings; distributed amplifier (DA); Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; feedback; Logic gates; Mathematical model; Power demand; transformer; wideband
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2013.2271614

This paper presents CMOS distributed amplifiers (DAs) using the proposed gate-drain transformer feedback technique. The feedback allows reuse of the traveling signal to achieve a high gain-bandwidth product while maintaining low power consumption of DAs. With the folded transmission lines and patterned ground shield, the miniaturized transformer has high quality factors and a well-controlled feedback coupling coefficient. Two DAs are realized using the proposed technique in both 0.18-μm and 90-nm CMOS technologies, respectively. The 0.18-μm CMOS DA achieves a gain of 9.5 dB with a 3-dB bandwidth of 32 GHz, and the noise figure (NF) ranges from 4.1 to 7.6 dB under a power consumption of 71 mW. Under a power consumption of 60 mW, the 90-nm DA demonstrates a gain of 7 dB, a bandwidth of 61.3 GHz, and an NF below 6.2 dB up to 40 GHz. The core areas of the 0.18-μm and 90-nm designs are only 0.58 and 0.41 mm 2 , respectively.