Variable-gain up-converter with current reuse for WCDMA wireless transmitters

In this paper a variable-gain up-conversion mixer based on a novel variable-transconductance input stage is presented. The proposed topology allows dc current reuse and reduces the overall transmitter power consumption in wideband code-division multiple access applications. Temperature compensation and decibel-linear characteristic are achieved by means of a control circuit providing a lower than ±1 dB gain error over a 46-dB dynamic range. A 3-dBm output compression point, 13-dB noise figure, and -45-dB adjacent-channel leakage power ratio are obtained under maximum gain conditions.