A fully integrated 5.35-GHz CMOS VCO and a prescaler

A 5.35-GHz monolithic VCO and a prescaler have been fabricated in a 0.25-mum CMOS process. The VCO has a tuning range of 336 MHz and phase noise of -117 dBc/Hz at a 1-MHz offset and 7-mW power consumption. The low phase noise is achieved by using only PMOS transistors in the VCO core and by optimizing the resonator layout. The prescaler utilizes a variation of the source coupled logic [1], and consumes only 4.1 mW at V-DD=1.5 V and 5.4 GHz. A second prescaler operating at 9.96 GHz and 2.5-V V-DD is also demonstrated.