Transmission in DCS1800, PCS1900, and WCDMA1900 is performed by a common
second RE power amplifier. In DCS1800 and DCS1900, transmission power is
set in a high transmission power mode at 33 dBm by a high-gain input
amplifier to activate an internal voltage follower of a bias circuit, and
in WCDMA1900, in a low transmission power mode at 28 to 29 dBm by a
low-gain input amplifier to inactivate the voltage follower. Switching of
the high and low transmission power modes and controlling the voltage
follower are performed according to a mode signal. In an RF power
amplifier module that transmits frequencies of GSM850, GSM900, DCS1800,
PCS1900, and WCDMA1900, it is possible to reduce the number of power
amplifiers and, for ramp-up and ramp-down of the GSM standard, to perform
high-speed control of an input bias voltage and reduce noise of a
transmission power of a wideband WCDMA.