This paper describes a 1 nA current reference designed in 180 nm and 350 nm CMOS technologies. The proposed design is an enhancement of Oguey’s reference circuit. This improved design provides a temperature stable current of 1 nA within the temperature range from −45◦C to 85◦C, with a simulated temperature coefficient (TC) of 388 ppm/◦C and 281 ppm/◦C in 180 nm and 350 nm technologies, respectively. The operating voltage for the proposed circuit ranges from 1.4 to 2.1 V in 180 nm design, with a power consumption of 126 nW@1.8 V. In 350 nm design the operating voltage is from 2.7 to 3.3 V, with a power consumption of 2.1 µW@3.3 V. Measurements of the proposed design fabricated in 350 nm technology are explained in detail in section 3.2.
