A Parallel Power Amplifier With a Novel Mode Switching Control

Two parallel operating power amplifiers (PAs) are controlled by a novel mode switch for high efficiencies at both the back-off power region and high power region. The mode switch is realized by the base-collector (BC) junction diode which reuses the dc current of the low power mode amplifier. A 836 MHz CDMA PA has been demonstrated using InGaP/GaAs heterojunction bipolar transistor with fully integrated matching component for small package and low cost. It shows a 13 mA idle current, 15.4% power added efficiency (PAE), ACPR1 at 16 dBm of the low power mode operation and a 40.5% PAE, ACPR1 at 28 dBm of the high power mode operation.