On-chip delay measurement circuit

Abstract

A novel On-chip delay measurement circuit is presented which is suitable for wide applications involving on-chip measurements, monitoring and process compensation. The circuit is based upon multiple characterization units consisting of ring oscillator, latches and counter. The delay unit used in ring oscillator defines the measurement resolution for the characterization unit. Each characterization unit has different delay cell with delay varying by few Pico-seconds (~1 to 5 picoseconds) with other one, which helps in increasing the resolution. All units give values based on their delay units and collectively all values forms a statistical space whose median gives the pulse width value. In this way, the circuit overcomes the limitations of earlier proposed on-chip measurement systems by offering high accuracy, high resolution and wide range of measurement using very few components. Silicon results on CMOS 40nm technology node for characterization of memory access time based upon proposed system are also presented.