A 5.67-8.75 GHz LC VCO with small gain variation for 2.4 GHz-band WLAN applications

Abstract

In this paper, a 5.67-8.75 GHz LC VCO with small gain variation and reconfigurable buffer for 2.4 GHz-band WLAN applications is presented and implemented in a Semiconductor Manufacturing International Corporation (SMIC) 55 nm CMOS process. The VCO gain is a strong function of the capacitance. For wide frequency tuning range meaning the large gain variation. The gain calibration scheme is proposed to obtain small gain variation across the frequency range. This letter proposes a reconfigurable buffer with adjustable amplitude, low jitter, and small supply coupling issues. The results show the proposed gain calibration scheme is very effective. The measured phase noise at 6.69 MHz offset is -123.2 dBc/Hz at 4.9 GHz output frequency.