Latched ring oscillator device for on-chip measurement of clock to output delay in a latch

摘要

A novel and useful apparatus and related method for on-chip measurement of the clock to output delay of a latch within an integrated circuit. The delay measurement mechanism enables measuring the time delay from the transition of the clock input to the data output of a latch. The output delay of the on-chip latch is measured by making the latch delay part of a ring oscillator and measuring its frequency of oscillation. A latch based delay stage is used to construct the ring oscillator in which a delayed short pulse derived from the input edge is used as the trigger for the latch. The latched ring oscillator mechanism of the invention can be used to measure the clock to output (C2Q) delay of on-chip latch devices.