A 2-nW 1.1-V self-biased current reference in CMOS technology

This paper presents the design of an ultra-low-power self-biased 400-pA current source. We propose the use of a very simple topology along with a design methodology based on the concept of inversion level. An efficient design methodology has resulted in a cell area around 0.045 mm(2) in the AMI 1.5-mum CMOS technology and power consumption around 2 nW for 1.2-V supply. Simulated and experimental results validate the design and show that the current source can operate at supply voltages down to 1.1 V with a good regulation (< 6%/V variation of the supply voltage) in a 1.5-mum technology.