A new superior-order curvature-corrected voltage reference will be presented. In order to improve the temperature behavior of the circuit, a double differential structure will be used, implementing both the linear and the superior-order curvature corrections. The superior-order curvature-correction will be implemented by taking the difference between two gate-source voltages of subthreshold-operated MOS transistors, biased at drain currents having different temperature dependencies: PTAT (ProporTional with Absolute Temperature) and PTAT2. The SPICE simulations confirm the theoretical estimated results, showing a temperature coefficient under 9.4 ppm/K for an extended input range 173 K < T < 423 K and for a supply voltage of 2.5 V and a current consumption of about 1 µA.

Keywords: Temperature behavior, Superior-order curvature-correction technique, Voltage references