A 30-MHz low-jitter high-linearity CMOS voltage-controlled oscillator

A fully monolithic voltage-controlled oscillator (VCO) with an on-chip timing capacitor and a maximum oscillation frequency of 30 MHz is reported. Using a novel on-chip servo loop, the VCO displays less than 0.17% nonlinearity in its voltage-frequency transfer function from 1 to 15 MHz without trimming. An improved circuit topology that provides a large swing on the timing capacitor allows the VCO to obtain a cycle-to-cycle jitter of less than 100 p.p.m. The circuit operates on a 5-V supply with a die size of 104 mil×154 mil.