A 3.0 – 3.6 GHz LC-VCO with ETSPC Frequency Divider in 0.18-micron CMOS technology

Abstract

This paper proposes the design, implementation, and measurement of a fully integrated voltage controlled oscillator (VCO) and frequency divider for multi-band transceivers in 0.18-micron IBM 7RF CMOS technology. The VCO is composed of a cross-coupled NMOS transistor-pair and LC tank as a core circuit and 4-bit digitally-switched capacitor block with linearly varying varactors for enhancement of the wide oscillation frequency bandwidth. A design of frequency divider is based on extended true-single-phase- clock (ETSPC) flip-flops with divide values ranging from 2 to 256 for very wide output frequency range. The measured results indicate that the LC-VCO frequency range is from 3.02 GHz to 3.55 GHz, and the phase noise is -108.89 dBc/Hz at 1 MHz offset from 3.55 GHz carrier. The power consumption of the LC-VCO with ETSPC frequency divider including all the buffers and other circuits is about 212 mW for 2.49 dBm of output power. The active area of the test chip occupies only 0.65×0.65 mm 2 and the whole chip size including the ESD protection circuits and pads is 1.5×1.5 mm 2.