Variable-gain power amplifier for mobile WCDMA applications

A single-chip linear power amplifier (PA) with >48-dB gain control range and >24-dBm output power with adjacent channel leakage power below -36 dBc is presented. The chip is realized using an AlGaAs-GaAs heterojunction-bipolar-transistor process and is aimed for 1.95-GHz mobile WCDMA applications. The amplifier consists of two blocks, the variable-gain amplifier, and the PA. The chip size is 1.3/spl times/1.1 mm/sup 2/ and it is mounted on an 8/spl times/8 mm/sup 2/ FR-4 type laminate with 26 pieces of 0402 surface-mountable discrete components composing a complete 50-/spl Omega/ input-output amplifier module. This paper presents the design of the two blocks, discusses issues related to their combination, and presents complete amplifier realization and measurement results.