Sub-1V ultra low-power voltage reference

This paper presents an optimized sublV voltage reference circuit based on the Body-Bias technique [1], which operates at power supply 1V or less. This reference circuit generates a voltage equal to the threshold voltage (at absolute zero temperature) of the transistor used in the design. To achieve zero temperature variations, it compensates temperature variations of thermal voltage, which is Proportional to Absolute Temperature (PTAT) with that of transistor´s threshold voltage, which is Compliment to Absolute Temperature (CTAT). Utilizing the concept of body-bias technique to put the transistors in deep sub-threshold region, successfully achieved ultra-low power design. Design Implementation in 0.18μm achieved a temperature coefficient of best 8PPM and an average Power consumption of the circuit is found to be 135nW.