A supply modulator for providing a first power supply voltage and a second power supply voltage to a first power amplifier and a second power amplifier, respectively, includes a first modulation circuit including a linear regulator and a switching regulator, the first modulation circuit being configured to generate a first modulation voltage in accordance with envelope tracking, and provide the first modulation voltage to the first power amplifier as the first power supply voltage; and a single inductor multiple output converter configured to generate a first output voltage and a second output voltage based on an input voltage having a fixed level, provide the first output voltage to the linear regulator of the first modulation circuit as a power supply voltage, and provide the second output voltage to the second power amplifier as the second power supply voltage.