0.55-1.8 V, 7.5 nW, 225.5 mV, CMOS-only subthreshold voltage reference
This Letter presents a wide supply voltage range, ultra-low power, and CMOS-only subthreshold voltage reference. A complementary-to-absolute-temperature (VCTAT) generator implemented by a standard VTH transistor and a high VTH transistor is used to obtain a negative temperature coefficient (TC) voltage. While, a proportional-to-absolute-temperature (VPTAT) generator adopts a unbalanced differential pair to achieve a positive TC voltage. With both VCTAT generator and VPTAT generator, the CMOS-only voltage reference circuit is proposed, which is implemented in a standard 0.18 mm CMOS process. The simulation results show that the mean output reference voltage is 225.5 mV at room temperature with a supply voltage as low as 0.55 V, meanwhile the output reference voltage achieves a TC of 21.9 ppm/°C with a temperature range from ¿20 to 80°C. With a supply voltage of 0.55 V and at room temperature, the current consumption is 13.6 nA and the power consumption is only 7.5 nW. The reference circuit correctly works with a supply voltage ranging from 0.55 to 1.8 V, and it obtains the line regulation of 0.0022%/V.