A 1.2nW, 2.1ppm/°C subthreshold CMOS voltage reference without resistors

A voltage reference with low temperature coefficient (TC), low supply voltage and ultra-low power consumption is presented. The proposed reference is made up of MOSFETs working in subthreshold region without resistors. Therefore the advantages of ultra-low power consumption and ultrasmall area can be obtained. The best TC is 2.1ppm/°C in a temperature range of -20°C to 80°C. The supply voltage ranges from 0.65V to 5.0V, and the power consumption is 1.2nW with 1V supply voltage. The power supply rejection ratio (PSRR) without any filter capacitor at 100Hz and 10MHz is lower than -49dB and -39dB, respectively.