Design of an Ultra-Compact 60-GHz Bi-Directional Amplifier in 65-nm CMOS

• Published in: IEEE microwave and wireless components letters Vol. 32; no. 4; pp. 343 - 346
• Main Authors: Cheng, Depeng, Chen, Xin, Chen, Qin, Li, Lianming, Sheng, Bin
• Format: Journal Article
• Language: English
• Published: IEEE 01.04.2022
• Subjects: 60 GHz; bi-directional amplifier (DBA); Bidirectional control; Capacitors; Circuit stability; CMOS; coupled line transformer; Gain; Gain measurement; Transistors; ultra-compact; Wideband
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2021.3123573

This letter presents an ultra-compact two-stage 60-GHz differential bi-directional amplifier (DBA) design in a 65-nm CMOS process. To satisfy the stability and gain requirements, a differential neutralized bi-directional common-source gain cell combined with the cross-coupled gm-boosting technique is proposed. In addition, a layout-symmetrical coupled line transformer is used as the inter-stage matching network to achieve broadband operation, reducing insertion loss and ensuring identical responses in both forward/backward modes. The proposed DBA achieves a peak gain of 16.1 dB with a 3-dB bandwidth of 15 GHz (52-67 GHz), maximum OP<inline-formula> <tex-math notation="LaTeX">_{\mathrm {1 \,\,dB}} </tex-math></inline-formula> of 5.1 dBm, <inline-formula> <tex-math notation="LaTeX">P_{\mathrm {SAT}} </tex-math></inline-formula> of 9.6 dBm, a peak PAE of 11.5% at 62 GHz, respectively, consuming 70 mW from a power supply of 1.2 V. The circuit core occupies an ultra-compact area of only 0.0675 mm 2 .