Abstract:Charge pump (CP) based PLL is one of the most popular techniques because of its wide capture range and zero static phase offset. An op-amp is used to achieve dynamic current matching in the conventional double op-amp CP. This paper proposes a CP, which adopts simple level shift source follower to match the output voltages of two current mirrors when the output voltage of CP changes. Because one of the high-speed op-amps is deleted, the power consumption and area are cut down without sacrificing the current matching performance. The proposed CP achieves less than 0.025% DC current mismatch with 400 μA charge pump current under 1.2V supply when the output voltage changes from 0.3V to 0.9V in a standard 55 nm CMOS process.