A 1.8-nW sub-1-V self-biased sub-bandgap reference for low-power systems

Abstract

An ultra-low power sub-bandgap voltage reference circuit fabricated in a standard 0.18-μm CMOS technology is proposed. Exploiting the negative temperature characteristics of V_BE and V_TH, a novel self-biased circuit configuration with a combination of a parasitic BJT and MOSFETs is employed to achieve a temperature-compensated sub-bandgap voltage reference with nanowatt power dispassion. The measurement results show that, the proposed circuit provides an average reference voltage of 261.6 mV with a variation coefficient of 0.86 %. The line regulation (LR) is 0.26%/V in a supply voltage range of 0.9 V to 1.8 V at 27 ℃, and the power supply rejection ratio (PSRR) is -49 dB at 100 Hz. With one-time trimming, measurements performed over a set of 18 samples shows an average temperature coefficient of 25.9 ppm/℃ in a temperature range from -20 to 100 ℃. The power dissipation is 1.8 nW with a supply voltage of 0.9 V at 27 ℃. The chip area is 0.0038 mm².