Design of a high-speed low-voltage (1V) charge-pump for wideband phase-locked loops

We have designed a new low voltage differential charge-pump for wideband phase-locked loops (PLL). The charge-pump operates at 500 MHz with a supply voltage of 1 V. The differential output voltage range of the cross-coupled charge-pump is 1.4 V. Improved current matching resulted in reduced reference spur levels at the PLL output. Simulations of a PLL showed spurious levels below -88 dBc. The circuit is implemented in a 0.18/spl mu/m CMOS process.

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