A temperature stabilized CMOS ring oscillator for a time-to-digital converter of a laser radar

A temperature stabilized CMOS ring oscillator for a time-to-digital converter of a laser radar has been designed. The ring oscillator is based on measuring the frequency of the ring oscillator by a frequency-to-voltage converter and locking that voltage to a stable voltage reference. The simulated temperature stability of the ring oscillator was less than 10 ppm//spl deg/C at all different corner points in temperature range of -10/spl deg/C to 70/spl deg/C. This corresponds to 0.1 mm//spl deg/C in a distance of 10 m. The frequency of the ring oscillator was approximately 653 MHz, giving a resolution of 128 ps.