2.2ppm/°C bandgap voltage reference with high-order temperature compensation

Abstract

A 2.2-ppm/°C voltage reference is proposed for use as an analog to digital conversion reference in readout application-specific integrated circuits. The proposed circuit uses resistors available for the standard CMOS process with opposite sign temperature coefficients. That enables a superposition of two bandgap schemes, one with downward concave and the other upward concave voltage temperature dependence. Using two similar schemes for the task allows topology matching of single circuit elements. The providen schematic is verified by simulation of the reference in 0.35 μm technology. The simulated reference provides a voltage of about 1.2 mV with the variation of ~300 μV in the temperature range -20 to 85°C. The operating temperature range is the reduced industrial grade, with a supply voltage of 3.3V, and an average consumption current of 6:4μA in the operating temperature range.