Multi-Rate DEM With Mismatch-Noise Cancellation for DCOs in Digital PLLs

Mismatches among frequency control elements in digitally-controlled oscillators can be a significant source of phase error in digital phase-locked loops (PLLs). This paper presents a multi-rate dynamic element matching technique and an adaptive mismatch-noise cancellation (MNC) technique that work together to address this problem. The two techniques operate in background during normal PLL operation, and the MNC technique has typical cold start convergence times of a few seconds.