Improve the dynamic matching of the source-switching charge pump for high-performance phase-locked loops

Conventional source-switching charge pump suffers from slow turning-off speed and intrinsic speed mismatch between its NMOS discharging path and PMOS charging path, which incur obvious dynamic mismatch. To alleviate the above problems, this paper proposes an improved source-switching charge pump, which achieves much better dynamic matching while maintains the same static matching. The proposed charge pump outputs less current noise and lowers the reference spur obviously, which makes it quite preferable for high-performance phase-locked loops.