Low temperature coefficient and low line sensitivity subthreshold curvature‐compensated voltage reference

Abstract

Summary A high‐order curvature‐compensated subthreshold voltage reference is proposed in this paper. The proposed curvature‐compensated voltage reference consists of two supply‐independent first‐order voltage references and a curvature compensation circuit. The supply‐independent first‐order voltage reference uses a negative feedback loop which improves the line sensitivity and eliminates the demand of operational amplifier, whereas the curvature compensation circuit provides high‐order temperature‐compensated output reference voltage. The proposed curvature‐compensated voltage reference provides an output reference voltage of 118.54 mV with a temperature coefficient of 21.5 ppm/ °C over a wide temperature range of −60 °C to 120 °C . The power supply rejection ratio and line sensitivity are observed as −68.64 dB (for the frequency range of 1 Hz to 100 Hz) and 0.035 %/V (for the supply voltage varies from 0.85 V to 2.5 V), respectively. The values of output noise at the frequencies of 1 kHz and 10 kHz without using any capacitive filter are obtained as 179.13 nV/ √ Hz and 123.87 nV/ √ Hz , respectively.