An On-Chip NBTI Sensor with Rise Transition Time Monitoring Circuit

An on-chip NBTI sensor based on measurement of rise transition time difference due to NBTI between a stressed and reference inverter is proposed that supports both ac and dc stress mode with very short measurement time of 130nsec. A new simple circuit with low area overhead is introduced to measure the rise transition time. The new sensor, with high correlation between Vthdegradation and its output voltage, has a resolution of 1.2mV per 0.5mV threshold voltage shift. Differentia structure of sensor eliminates the effect of common-mode environmental variation such as temperature. A 180nm CMOS technology model is used for simulation of the sensor. The average power consumption of this sensor is 428μw in stress mode and 54μw during measurement mode.The implemented layout area is 101×18 2 m . Analysis confirms sensor performance with 11% error in comparison with simulation results.

Keywords:

NBTI , Reliability , Sensor , Slew Rate