A 109 nW, 44 ppm/°C CMOS Current Reference with Low Sensitivity to Process Variations

We present the design of a circuit, implemented in a standard 0.35 μm CMOS process, that provides a bias current practically independent of temperature and process variations. Experimental results show that the proposed circuit provides a reference current with a temperature coefficient of 44ppm/°C over a range from 0 to 80 °C. The reference current is generated by exploiting a MOS transistor as current defining element, instead of a resistor, allowing us to achieve a relative standard deviation due to process variations of 2% . The minimum supply voltage is 1.3 V and the minimum supply current is 36 nA. The line sensitivity is 569ppm/V. The chip area is 0.035mm
²
.