High efficiency and linear dual chain power amplifier without/with automatic bias current control for CDMA handset applications

New architectures of the dual chain InCaP MMIC power amplifiers withouuwith automatic bias current control (ABC
²
) have been developed for improving efficiency in the low-power region while maintaining the high linearity for all Pout regions. For low standby current less than 25 mA, the amplifiers initially operate using small HBT arrays. For small chip sue, high load impedance in low-power region, and efficient power combining in high-power region, phase-compensating L-C matching circuits using lowpass and high-pass networks are used. A new simple power detection and bias current control circuit is employed to the power amplifier, resulting in automatic gain control for Pout variation. The fabricated (ABC
²
) power amplifier module shows good ACPR more -48 dBc over all Pouts, and high efficiency of 6 % PAE (conventional 3.5~4%) at Pout=9 dBm, and 37.5 % PAE at Pout=28 dBm.