A CMOS Distributed Amplifier With Distributed Active Input Balun Using GBW and Linearity Enhancing Techniques

A CMOS distributed amplifier (DA) with distributed active input balun is presented that achieves a gain-bandwidth product of 818 GHz, while improving linearity. Each gm cell within the DA employs dual-output two-stage topology that improves gain and linearity without adversely affecting bandwidth (BW) and power. Comprehensive analysis and simulations are carried out to investigate gain, BW, linearity, noise, and stability of the proposed gm cell, and compare them with conventional gm cells. Fabricated in a 65-nm low-power CMOS process, the 0.9-mm² DA achieves 22 dB of gain and a P_1dB of 10 dBm, while consuming dc power of 97 mW from a 1.3-V supply. A distributed balun, designed and fabricated in the same process, using the same gm topology achieves a BW larger than 70 GHz and a gain of 4 dB with 19.5-mW power consumption from 1.3-V supply.