A low-voltage PLL with a current mismatch compensated charge pump

A low-voltage phase-locked loop (PLL) circuit having a charge pump (CP) with a novel negative feedback replica bias scheme for current mismatch compensation is demonstrated. A prototype 400-MHz PLL circuit operating at 0.65-V is fabricated with 180-nm standard CMOS process. Measurement results show that current mismatch compensation is successfully achieved. Our PLL consumes only 140-μW.