Aspects of the disclosure provide an amplifier. The amplifier includes a first path, a second path and a drain bias circuit. The first path includes a first transistor that operates in a saturation region to generate a first current in response to an input signal. The first current has a first polarity third-order coefficient. The second path includes a second transistor that generates a second current in response to the input signal. The drain bias circuit is configured to bias a drain terminal of the second transistor separately from the first transistor such that the second transistor operates in a linear region to generate the second current having a second polarity third-order coefficient. The second current is combined with the first current to reduce a third-order inter-modulation in the combined current.