A CDMA InGaP/GaAs-HBT MMIC Power Amplifier Module Operating With a Low Reference Voltage of 2.4 V

This paper describes circuit design and measurement results of our newly developed InGaP/GaAs-HBT MMIC power amplifier (PA) module which can operate with 2.4-V low reference and low supply voltages of its on-chip bias circuits. To achieve the low-reference voltage operation, the following two new circuit design techniques are incorporated into the power amplifier: 1) AC-coupled, divided power stage configuration with two different kinds of bias feeding (voltage and current drive and only current drive) and 2) successful implementation of a diode linearizer built in the power stage. Theses two techniques allow the PA to offer smooth output transfer characteristics over a wide temperature range. Measurement results done under the conditions of 900 MHz, a 3.5-V collector voltage for power stage, and 2.4-V reference and collector voltages for the bias circuits show that the PA module meets J-/W-CDMA power and distortion requirements sufficiently over a wide temperature range from -10degC to 90degC while keeping a low quiescent current of less than 65 mA. For J-CDMA modulation, the module can deliver a 27.5-dBm output power (P_out), a 40% PAE, and a -50-dBc ACPR, while a 28-dBm P_out, a 42% PAE, and a -42-dBc ACLR are achieved for W-CDMA modulation.