A 0.6-V, 1.56-nW, 5.87-ppm/°C, 0.23%/V CMOS-Only Subthreshold Voltage Reference with the Threshold Voltage Difference

A low-supply, nano-watt level CMOS-only voltage reference is proposed in this paper for the internet-of-things, wireless sensor networks, and implantable biomedical chips. The threshold voltage fluctuation caused by the process variation can be suppressed to within 30 mV through utilizing the threshold voltage difference between thick-gate transistors and thin-gate transistors. Benefiting from the self-regulating technology and subthreshold operation, the circuit branches and supply voltage are significantly decreased compared with the previous CMOS voltage reference, which facilitates low power design. What's more, the proposed CMOS voltage reference also circumvents resistors, bipolar transistors, and operational amplifiers. The simulation results demonstrate that the proposed CMOS voltage reference consumes a quiescent power consumption of 1.56-nW at 0.6 V, providing an average voltage reference of 305.32 mV using a 0.18-mu m CMOS process. The mean temperature coefficient of the voltage reference is 5.87 ppm/degrees C with a standard deviation of 2.33 ppm/degrees C over a temperature range of - 40 degrees C similar to 130 degrees C. The linearity sensitivity is 0.23%/V across a supply voltage range of 0.6 V to 1.8 V. Furthermore, the power supply ripple rejection below 100 Hz and the mean output noise @10 Hz can reach - 58.6-dB and 3.99 mu V/root Hz. The simulation results match the theoretical analysis.

Automated summary

This paper proposes a low-supply, nano-watt level CMOS-only voltage reference for the internet-of-things, wireless sensor networks, and implantable biomedical chips. By utilizing the threshold voltage difference between thick-gate transistors and thin-gate transistors, the threshold voltage fluctuation caused by process variation can be suppressed. The circuit branches and supply voltage are significantly decreased compared with previous designs, allowing for low power design.