Abstract: This paper presents a fully integrated wideband LC voltage-controlled oscillator (VCO) with small tuning gain fluctuation.This VCO is designed for a dual-conversion low-IF architecture (DLIF) DTV tuner.A switched varactor array is proposed to suppress tuning gain fluctuation for the performance of the phase locked loop (PLL).The whole VCO was implemented in a 0.18μm CMOS process.The measured results show -126dBc/Hz phase noise at 1MHz offset frequency.The measured tuning range is 860MHz (53.8%) from 1.17 to 2.03GHz with the tuning gain from 69 to 93MHz/V.Power consumption is about 9mW with a 1.5V supply voltage.

Key words: wideband, tuning gain, switched capacitor array, switched varactor array, differentially tuned, VCO