An apparatus for and method of a supply modulator (SM) for a power amplifier (PA) is provided. The apparatus includes a buck-boost converter, including a supply input connected to a battery voltage (Vbat), and an output; a switch and capacitors module, including a first input connected to the output of the buck-boost converter, and a second input; a buck (dual) converter, including a supply input connected to Vbat, an input connected to the output of the buck-boost converter, and an output connected to the second input of the switch and capacitors module; a linear amplifier (LA), including a supply input connected to the output of the buck-boost converter, an input, and an output connected to the second input of the switch and capacitors module; and the PA, including a supply input connected to the output of the buck (dual converter, an input for receiving a radio frequency (RF) signal, and an output for outputting an RF signal.