A 480μW 2GHz ultra low power dual-modulus prescaler in 0.25μm standard CMOS

A dual modulus 128/129 prescaler is presented, consuming 480 mu W at a power supply voltage of 1.8V and an input frequency of 2GHz or 98 mu W at a power supply voltage of 1.5V and an input frequency of 1GHz. The prescaler was realized in Infineon 0.25 mu m standard CMOS process using single-phase docked flipflops in the phase-switching prescaler architecture. The circuit was optimized for minimal power drain, maintaining a maximum operating frequency of at least 2GHz. Measured maximal frequency of operation of the prescaler was 2.5GHz. A co-integration of the prescaler with a voltage controlled LC-oscillator showed no detoriation of the -110dBc/Hz phase-noise performance of the VCO at 100kHz frequency offset, thus proving the practical use of the circuit for synthesizers.