A device and method for amplifying signals is provided. The device can have an input to receive an input signal having a first desired signal on a first carrier, a second desired signal on a second carrier, and one or more interfering signals. The device can have a first carrier aggregation (CA) chain for use with the first desired signal and a second CA chain for use with the second desired signal. The first and second CA chains can be coupled to the input. The first and second CA chains can have a plurality of transconductance stages. Each of the transconductance stages can be configured as a high impedance stage or a low impedance stage. The transconductance stages can be selectively activated to incrementally adjust the transconductance, and therefore the input impedance, of each of the CA chains.