Design of Adaptive Multimode RF Front-End Circuits

Migration towards higher data rates and higher capacities for multimedia applications, and provision of various services (text, audio, video) from different wireless standards with the same device require integrated designs that work across multiple standards, can easily be reused, and achieve maximum hardware share at minimum power consumption. This can be achieved by using adaptive circuits that are able to trade off power consumption for performance. The design of an adaptive multimode image-reject downconverter (oscillator and two mixers) is presented in this paper. In the highest performance mode, the image-reject downconverter (the quadrature mixers) has an IIP3 of +5.5 dBm, a single-side band noise figure of 13.9dB and a conversion gain of 1.4 dB, while drawing 10mA from a 3 V supply. The adaptive oscillator achieves -123 dBc/Hz phase noise at 1MHz offset from a 2.1 GHz carrier with a bias current of 6 mA in the highest performance mode. Adaptivity in the downconverter is achieved by trading off RF performance for current consumption, ranging from 10 mA for the relaxed mode (e.g., DECT) to 20 mA in the highest performance mode (e.g., DCS1800) of operation