Analysis, Design, and $X$-Band Implementation of a Self-Biased Active Feedback $G_{m}$-Boosted Common-Gate CMOS LNA

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper explores the use of active feedback to boost the transconductance of a common-gate (CG) low-noise amplifier and achieve simultaneous low noise and input power match. Unlike transformer coupled topologies, the CG input stage is dc-coupled to a self-biased common-source feedback amplifier (for <formula formulatype="inline"><tex Notation="TeX">$g_{m}$</tex></formula> boosting), thus eliminating the need of external bias circuitry. Noise and intermodulation analysis with and without <formula formulatype="inline"><tex Notation="TeX">$g_{m}$</tex> </formula> boosting are extensively studied yielding closed-form expressions of the noise figure (NF) and third-order input-referred intercept point (IIP3) that are useful for circuit design and optimization. A 9.6-GHz differential prototype implemented in a 0.18-<formula formulatype="inline"><tex Notation="TeX">$\mu$</tex> </formula>m technology using only NMOS transistors, achieves a minimum NF of 4 dB, an IIP3 of <formula formulatype="inline"><tex Notation="TeX">${-}$</tex> </formula>11.3 dBm, a return loss of <formula formulatype="inline"><tex Notation="TeX">${-}$</tex> </formula>17 dB, and a transducer gain of 18 dB while dissipating 10 m (excluding buffer circuit) from a 1.8-V supply voltage. The active chip area is 0.11 <formula formulatype="inline"><tex Notation="TeX">$\mu$</tex></formula>m<formula formulatype="inline"> <tex Notation="TeX">$^{2}$</tex></formula>. </para>