| Title |
A Dual-compensated Charge Pump for Reducing the Reference Spurs of a Phase Locked Loop |
| Authors |
이동건(Lee, Dong-Keon) ; 이정광(Lee, Jeong-Kwang) ; 정항근(Jeong, Hang-Geun) |
| Keywords |
PLL ; Charge Pump ; Dual Compensation ; Current Mismatch ; Reference Spur |
| Abstract |
The charge pump in a phase-locked loop is a key block in determining reference spurs of the VCO output signal. To reduce reference spurs, the current mismatch in the charge pump must be minimized. This paper presents a dual compensation method to reduce the current mismatch. The proposed charge pump and PLL were realized in a 0.18μm CMOS process. Measured current matching characteristics were achieved with less than 1.4% difference and with the current variation of 3.8% in the pump current over the charge pump output voltage range of 0.35-1.35V at 1.8V. The reference spur of the PLL based on the proposed charge pump was measured to be -71dBc. |