2.64 pJ reference-free power supply monitor with a wide temperature range

Power supply noise in current nanometer technologies represents a growing risk, specially because of the uncertainties it produces in the critical paths delays which can result in erroneous computations. To tackle with these issues and to have a better power management, power supply monitors are necessary. Traditional approaches use an external reference or are very sensitive to temperature and process variations. In this work we propose a monitor that works without an external reference and is hardened against thermal and process variations. The sensor was designed in the 40 nm CMOS technology node, operating at 1.1 V and has been validated for a temperature range of -40 °C to 125 °C covering all process corners. The sensor is able to detect voltage fluctuations of at least 45 mV, wider than 300 ps in the worst technology corner with a maximum latency of 600 ps and an energy consumption per measurement of 2.64 pJ.