A Sub-nW, 8T Current Reference Consuming Constant Power w.r.t Process & Temperature

The paper presents an eight transistor (8T) pico- watt current reference with a novel method of rectifying the problem of exponential power increase w.r.t temperature in traditional sub-nW references. The proposed current reference is obtained by modifying the traditional beta-multiplier architecture to scale- down the power consumption without sacrificing area. The constancy of power consumption w.r.t temperature is achieved by exploiting the voltage-current characteristics of a leakage transistor in the modified architecture. The proposed current reference, implemented in UMC 55nm technology, occupies an area of 0.00035mm². It is designed for a current of 60pA and achieves an accuracy of 19 ppm/°C over a wide temperature range of -55°C to 125°C. The reported line sensitivity for the current reference is 0.07%/V in the supply range of 1.2V - 4V. Post-trim results show a constant power consumption of 144pW w.r.t temperature and process variations @1.2V supply.