A CMOS dual-band fractional-n synthesizer with reference doubler and compensated charge pump

A fully integrated dual-band frequency synthesizer in 0.35 /spl mu/m CMOS technology achieves a phase noise of -141 dBc/Hz at 1.25 MHz offset in the PCS band with a reference frequency doubler. Fractional spurs are reduced by 8.6 dB at 50 kHz offset with a replica compensated charge pump.