A circuit comprising: a replica input transistor comprising a control node configured to be coupled to a control node of an input transistor of an RF circuit (240, 300, 400, 700); a first replica cascode transistor coupled in series with the replica input transistor, the first replica cascode transistor comprising a control node configured to be coupled to a control node of a first cascode transistor of the RF circuit (240, 300, 400, 700) wherein the first cascode transistor is coupled in series with the input transistor; and an active current source circuit (104, 106, 110, 232) having a first output coupled to the control node of the replica input transistor, the active current source circuit (104, 106, 110, 232) configured to set a current flowing through the first replica cascode transistor and the replica input transistor to a predetermined value by adjusting a voltage of the control node of the replica input transistor; characterized by an active cascode biasing circuit (120, 134, 250) comprising a first output coupled to the control node of the first replica cascode transistor and configured to be coupled to the control node of the first cascode transistor, the active cascode biasing circuit configured to set a voltage at a drain of the replica input transistor, which is connected to a source of the first replica cascode transistor, to a predetermined voltage by adjusting a voltage of the control node of the first replica cascode transistor, wherein the active cascode biasing circuit (120, 134, 250) comprises an amplifier having a first input coupled to the drain of the replica input transistor, a second input coupled to a bias reference voltage node, and an output coupled to the control node of the first replica cascode transistor, further comprising a second replica cascode transistor coupled in series with the first replica cascode transistor, the second replica cascode transistor comprising a control node configured to be coupled to a control node of a second cascode transistor of the RF circuit coupled in series with the first cascode transistor, wherein the active cascode biasing circuit (120, 134, 250) further comprises a second output coupled to the control node of the second replica cascode transistor, wherein the active cascode biasing circuit (120, 134) comprises a level shifting circuit coupled between the first output and the second output of the active cascode biasing circuit (120, 134). a replica input transistor comprising a control node configured to be coupled to a control node of an input transistor of an RF circuit (240, 300, 400, 700); a first replica cascode transistor coupled in series with the replica input transistor, the first replica cascode transistor comprising a control node configured to be coupled to a control node of a first cascode transistor of the RF circuit (240, 300, 400, 700) wherein the first cascode transistor is coupled in series with the input transistor; and an active current source circuit (104, 106, 110, 232) having a first output coupled to the control node of the replica input transistor, the active current source circuit (104, 106, 110, 232) configured to set a current flowing through the first replica cascode transistor and the replica input transistor to a predetermined value by adjusting a voltage of the control node of the replica input transistor; characterized by an active cascode biasing circuit (120, 134, 250) comprising a first output coupled to the control node of the first replica cascode transistor and configured to be coupled to the control node of the first cascode transistor, the active cascode biasing circuit configured to set a voltage at a drain of the replica input transistor, which is connected to a source of the first replica cascode transistor, to a predetermined voltage by adjusting a voltage of the control node of the first replica cascode transistor, wherein the active cascode biasing circuit (120, 134, 250) comprises an amplifier having a first input coupled to the drain of the replica input transistor, a second input coupled to a bias reference voltage node, and an output coupled to the control node of the first replica cascode transistor, further comprising a second replica cascode transistor coupled in series with the first replica cascode transistor, the second replica cascode transistor comprising a control node configured to be coupled to a control node of a second cascode transistor of the RF circuit coupled in series with the first cascode transistor, wherein the active cascode biasing circuit (120, 134, 250) further comprises a second output coupled to the control node of the second replica cascode transistor, wherein the active cascode biasing circuit (120, 134) comprises a level shifting circuit coupled between the first output and the second output of the active cascode biasing circuit (120, 134).