An analog-to-digital converter includes a ring oscillator having an input for receiving an analog signal, a coarse counter including a maximum length sequence generator having an input coupled to the output of the ring oscillator, a fine counter including a Johnson counter having an input coupled to the output of the ring oscillator, and a difference generator having a first input coupled to the output of the coarse counter, a second input coupled to the output of the fine counter, and an output for providing a digital signal corresponding to the analog signal.