Low noise amplifier

Abstract

A low-noise amplifier circuit to convert a single-ended input into a dual-ended output includes an input transconductance stage circuit, including a first MOS transistor coupled in parallel with a second MOS transistor; a current buffer circuit, including a third MOS transistor coupled in parallel with a fourth MOS transistor; each of the first, second, third, and fourth transistors having a body, gate, source, and drain; the input transconductance stage circuit and the current buffer circuit being cascode coupled, forming a cascode amplifier configuration; the single-ended input being at the source of one of the first and second transistors in the input transconductance stage circuit; the dual-ended output being a differential output across the drain of the third transistor and the drain of the fourth transistor; the first and second transistors of the input transconductance stage circuit being cross-coupled, wherein the body of the first transistor is coupled to the source of the second transistor, and the body of the second transistor is coupled to the source of the first transistor; and the third and fourth transistors of the current buffer circuit being cross-coupled, wherein a first capacitance is coupled between the gate of the third transistor and the source of the fourth transistor, and a second capacitance is coupled between the gate of the fourth transistor and the source of the third transistor.