Design of on-chip power noise sensing circuit and its applications

The fluctuations on power supply lines affect the operation and performance of the integrated circuits such as timing mismatches and functional failures. In this paper, we propose, implement and measure a sensing circuit to measure the peak of the overshoot and undershoot of the power supply noise. Using the sensing circuit output results, the magnitude of the actual noise coupled inside the on-chip power distribution network can be identified, and the probability of failure can be predicted. In the embedded sensing circuit, the analog noise is processed on-chip and is encoded to a digital value. Therefore, the limitations of PAD and the bonding wire parasitics are eliminated and better measurement accuracy can be achieved. The proposed sensing circuit was fabricated using 180nm CMOS process, the test flow for using sensing circuit was proposed, and was applied to measure the the peak overshoot and undershoot of power supply noise of an I/O transmitter circuit in operation. The measurement results of overshoot and undershoot of transmitter´s switching noise are 2.6V and 1.1V, respectively for 1.8V supply voltage. The sensing circuit is also applied to measure the magnitude of the on-chip noise caused by externally injected EMI noise using bulk current injection (BCI) method.