A three terminal varactor for RF IC's in standard CMOS technology

A three terminal metal-oxide-silicon varactor operated between accumulation and deep depletion is proposed for RF IC's. Prototypes, realized in a 0.35 /spl mu/m standard CMOS technology, show a 3.1:1 capacitance tuning. The corresponding minimum Q is 23 at 1800 MHz. The proposed varactor lends itself as tuning element of VCO's in highly integrated CMOS transceivers.