A 2 GHz Δ Σ fractional-N frequency synthesizer in 0.35 µm CMOS

A 2 GHz fractional-N frequency synthesizer for telecommunications applications is presented. The synthesizer includes a multiple-modulus CMOS prescaler capable of operating at input frequencies of up to 2.15 GHz with a power dissipation of 12.5 mW, a third-order MASH ΔΣ-modulator that controls the modulus of the prescaler, and a phase detector and chargepump that doesn´t suffer from dead-zone problems. The synthesizer achieves a close-in phase noise of-79 dBc/Hz while dissipating only 22.6 mW from a 2.7 V supply. The synthesizer has been implemented in a 0.35 µm CMOS technology.