Method and apparatus for configuring a transmitter circuit to support linear or polar mode. In the linear mode, a baseband signal is specified by adjusting the amplitudes of in-phase (I) and quadrature (Q) signals, while in the polar mode, the information signal is specified by adjusting the phase of a local oscillator (LO) signal and the amplitude of either an I or a Q signal. In an exemplary embodiment, two mixers are provided for both linear and polar mode, with a set of switches selecting the appropriate input signals provided to one of the mixers based on whether the device is operating in linear or polar mode. In an exemplary embodiment, each mixer may be implemented using a scalable architecture that efficiently adjusts mixer size based on required transmit power.