Technology-caused performance limitation of the common-gate LNA

Abstract

In this paper, the performance limitation of common-gate LNAs (CG-LNAs) caused by short channel effects is presented. The analysis is based on equations, which describes the behavior of the MOSFET including the noise sources in all possible regions of operation. From these equations, the input time constant τin is defined as one characteristic performance figure of the used CMOS technology. The bias dependent limitation of the noise figure N F and minimum input reflection coefficient min (S 11,dB ) is derived in dependence of τin. The paper shows furthermore the advantage of biasing the CG-LNA in the moderate inversion region.

An Inductor-less Sub-mW Low Noise Amplifier for Wireless Sensor Network Applications

“…1(c) [12]. Input impedance of CG amplifier is the source terminal impedance (1/g m ) of the amplifying transistor, so the trans-conductance of the input transistor and thus the gain of the amplifier are set by the input matching condition.…”