Abstract

This article presents a low-power, high-linearity cascodetype low noise amplifier (LNA) with 36 dB of variable gain for the WIDE Code Division Multiple Access systems. By enhancing the substrate resistance of a common gate transistor along with adopting multiple-gate technique, the linearity is significantly improved. Shunt-current steering is adopted for smooth gain control. Step gain mode is used to further increase the gain control range. The main common source transistor is disabled in attenuation mode, saving unwanted power consumption. Measurements show maximum gain of 12.3 dB with S11 of 19.5 dB, and S22 of 14 dB. The total gain control range is 36 dB. NF is measured as 2 dB and two-tone test shows 9.1 dBm of IIP3. Implemented in 0.13-m CMOS technology, the LNA consumes only 1.6 mA at maximum gain mode and only 0.2 mA in attenuation mode from 1.2 V supply. Its die size is 0.3 mm2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1385–1388, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop. 24320