Pulse width controlled PLL/DLL using soft thermometer code

Abstract

This paper demonstrates pulse width controlled PLL and DLL using a soft thermometer code. The oscillation frequency control in the PLL and the delay control in the DLL are conducted by a mostly digital with one bit analog code. Both of our PLL/DLL do not use an area-consuming capacitor, resulting in small silicon area implementation. A 65nm CMOS process uses only 120μm×30μm area for the PLL+DLL. They realized 2.80GHz operation consuming 1.35mW/4.65mW with 1.60ps/1.78ps rms jitter from the PLL/DLL output signals.