A Low Current Mismatch High Swing Charge Pump for High Speed Phase Locked Loop

Abstract

Based on 28nm CMOS process, a low current loss and high swing charge pump suitable for high speed PLL circuit is designed and verified under 1.05V voltage supply. by adopting a low voltage and high output impedance current mirror structure with OPA compensation, the charge-discharge current is accurately matched and the output swing is expanded. Meanwhile, the output jitter caused by charge injection and charge sharing is reduced significantly by the adoption of the differential output stage with unity-gain buffer. the results show that the charge-discharge current mismatch rate is less than 1% while the absolute current offset rate is less than 0.7% under the output voltage of 0.1~0.95V. As for the output voltage of 0.16~0.87V, the charge-discharge current mismatch rate is less than 0.05% with the current absolute offset rate below 0.1%. Moreover, the voltage glitch of the output does not exceed 40 μV during the on-off process of the CP.