Digital Controlled Oscillator

A monolithically integrated, digitally controlled oscillator is presented. It has an output frequency range from 18.9 Hz to ≫ 20 MHz, the long term stability of a quartz oscillator and a short term clock edge uncertainty with a standard deviation of 0.4 ns. The digital frequency control is fully linear with a resolution of 18.9 Hz. The only required external component is a reference quartz. The circuit operates from a single 5 V power supply and is fabricated in a 1.5 μm, double metal, single poly, CMOS process. The chip area is 4.1 mm
²
.