A picopower temperature-compensated, subthreshold CMOS voltage reference

作者：Albano Domenico^*; Crupi Felice; Cucchi Francesca; Iannaccone Giuseppe

来源：International Journal of Circuit Theory and Applications, 2014, 42(12): 1306-1318.

DOI：10.1002/cta.1925

• voltage reference
• subthreshold circuit
• temperature compensation
• CMOS analog design
• variability-aware design

A voltage reference consisting of only two nMOS transistors with different threshold voltages is presented. Measurements performed on 23 samples from a single batch show a mean reference voltage of 275.4mV. The subthreshold conduction and the low number of transistors enable to achieve a mean power consumption of only 40pW. The minimum supply voltage is 0.45V, which coincides with the lowest value reported so far. The mean TC in the temperature range from 0 to 120 degrees C is 105.4ppm/degrees C, while the mean line sensitivity is 0.46%/V in the supply voltage range 0.45-1.8V. The occupied area is 0.018mm(2). The power supply rejection rate without any filtering capacitor is -48dB at 20Hz and -29.2dB at 10kHz. Thanks to large area transistors and to a careful layout, the coefficient of variation of the reference voltage is only 0.62%. We introduce as a new figure of merit, the voltage temperature parameter (VTP), which gives a direct measure of the overall percentage variation of the reference voltage on the typical 2D domain of supply voltage and temperature. For the proposed circuit, the average VTP is 1.70% with a standard deviation of 0.21%. In order to investigate the effect of transistor area on process variability, a 4X replica of the proposed configuration has been fabricated and tested as well. Except for LS, the 4X replica doesn%26apos;t exhibit any appreciable improvement with respect to the basic voltage reference.

• 出版日期2014-12