Cell-Based Aging Sensor Using Built-In Speed Grading

Built-In Speed Grading (BISG) is a technique that measures the maximum operating speed (Fmax) of a circuit under test in silicon. Traditionally, it has been used in supporting performance debugging as well as Dynamic Voltage and Frequency Scaling. Recently, it has also been used to accelerate the detection of infant-mortality-prone devices and lifetime prediction during the stress test process. In this paper, we demonstrate that it can be used as an effective aging sensor. Compared to previous work, our BISG design presented in this paper enjoys an area reduction of 43.4%. It supports a wide clock frequency range of [40MHz, 1.25GHz] using only a 90nm CMOS process while achieving a fine-tuning resolution of 1%. Furthermore, it is made of standard cells and thereby rendering easy process migration. These above features combined make it not only a cost-effective but also a trustworthy on-chip aging sensor.