A Ring Ocillator Based Reliability Monitor

Due to the technology nodes further scale, variabilities continue to be a challenge for IC design. The variability is mainly classified as IR-drop, temperature change and aging. We mainly discussed the first two parts in this paper. Overheating can damage the chip permanently and excessive IR-Drop can greatly affect voltage sensitive digital blocks. In order to avoid these damages and make better adaptation, we need to differentiate these variabilities. In this paper, a 32nm ring oscillator based temperature sensor with IR-Drop monitor was presented. Different from traditional sensors, the proposed sensor can monitor IR-Drop in-field which avoid its effect on temperature measurement. The IR-Drop monitor is sensitive to variations larger than 100mV. Meanwhile, the temperature sensor block has a wide temperature measurement range. The sensor's temperature measurement period could be close to 10us,which helps to establish real-time thermal management. With its help, we can improve chip reliability. All these parts can be easily integrated into a chip due to its all-digital cells. The sensor occupies less than 0.0 1mm
²
area and achieves a resolution of 0.5°C.