Patent ID: 6977553

Claim:
A low noise amplifier (LNA), comprising: an input stage to amplify an input signal, the input stage having a transconductance that has reduced gain variations in response to changes in process and environmental conditions; wherein the input stage includes a first Metal Oxide Semiconductor (MOS) transistor to amplify the input signal, the first MOS transistor operated in a triode region; wherein the first MOS transistor has a size; a second MOS transistor arranged with the first MOS transistor in a cascode configuration, the second MOS transistor having a size and operated in a saturation region; an input switch ratio of the size of the second MOS transistor to the size of the first MOS transistor is greater than two; a bias circuit in communication with the first MOS transistor and the second MOS transistor; wherein the bias circuit includes a first MOS device having a size and a second MOS device having a size, to generate first and second voltages for biasing the input stage first MOS transistor and the input stage second MOS transistor; wherein a bias switch ratio of the size of the second MOS device to the size of the first MOS device is greater than one; wherein the bias circuit further includes a third MOS device having a size, to bias the first MOS device into a triode region; and the second MOS device is operated in a saturation region.