Patent ID: 7679436

Claim:
A low noise amplifier including at least one circuit branch, a first circuit branch comprising at least first and second amplifying elements coupled to cooperate in amplifying an input signal, and switching means to switch on and off the amplifier, characterized in that the first amplifying element has an input node to receive said input signal, and wherein said switching means are only coupled to the second amplifying element to switch on and off the amplifier by acting on said second amplifying element, wherein the first amplifying element is a first common gate transistor, and the second amplifying element is a first common source transistor, and wherein the drain of the first common gate transistor is connected to the gate of the first common source transistor, wherein the gate of the first common source transistor receives a signal from the drain of the first common gate transistor, and wherein the gate of the first common source transistor is coupled to drain of the first common gate transistor through a first impedance, the value of said first impedance being selected at least in part to couple a signal at the drain of the first common gate transistor to the gate of the first common source transistor, and wherein a second impedance is connected between the source of the first common source transistor and the drain of the first common gate transistor, the value of said second impedance being selected at least in part to prevent a signal at the drain of the first common gate transistor from entering into the first common source transistor.