Patent ID: 10191106

Abstract:
Methods and apparatus for identifying a process corner are provided. Provided is an exemplary method for identifying a process corner of an integrated circuit (IC). The IC has a first asymmetrical ring oscillator (ARO1) including pull-up transistors that have a low threshold voltage (LVT) and pull-down transistors that have a regular threshold voltage (RVT), and has a second asymmetrical ring oscillator (ARO2) including pull-up transistors that have an RVT and pull-down transistors having an LVT. The exemplary method includes applying an ultra-low power supply voltage to the ARO1 and the ARO2 that causes the integrated circuit to operate near a verge of malfunction, measuring an output frequency of the ARO1, measuring an output frequency of the ARO2, calculating a calculated ratio of the output frequency of the ARO1 and the output frequency of the ARO2, and comparing the calculated ratio to a fiduciary ratio to identify the process corner.