A 900 MHz, 2.7 V highly linear driver amplifier using 0.5 µm Si BiCMOS

A highly linear driver amplifier for 900 MHz cellular transmitter IC is presented. The amplifier operates from a 2.7 V to 3.3 V supply. At 2.7 V, ACPR (Adjacent Channel Power Ratio) of transmitter IC is as high as 50 dBc with an output power of 8.7 dBm. The high ACPR of transmitter IC is due to the high linearity of driver amplifier. To improve linearity of driver amplifier, we also investigate the appropriate emitter degeneration inductance at constant power by Volterra-series analysis. The driver amplifier is fabricated using a 0.5 µm BiCMOS process.