Generating all 2-transistor circuits leads to new wide-band CMOS LNAs

This paper presents a methodology that systematically generates wide-band CMOS Low Noise Amplifiers (LNAs), assuming that MOSFETs are exploited as a Voltage Controlled Current Source (VCCS). Using graph theory, ALL 2-VCCS LNAs are generated, and subsequently implemented using 2 NMOS transistors. Next to well-known circuits, two new wide-band LNAs are found. The most promising has been realized using an industrial 0.35µm CMOS process. Measurements show a 900 MHz bandwidth, VSWRIN<1.6, variable forward gain from 6 to 11dB and reverse isolation better than 30dB. At maximum gain, IIP2 is +15dBm and IIP3 is +1dBm, while NF is better than 4.5dB. The LNA drains only 1.5mA at 3.3V supply and the die area is 0.06mm².