A Curvature Coefficient Canceled High Precision Low Temperature Drift CMOS Bandgap Reference
Ping Li · China Integrated Circuit · 2008
The traditional bandgap voltage reference employs a linear PTAT voltage to compensate the temperature dependence of Vbe of the bipolar transistor. Because the temperature dependence of Vbe is not purely first order, the output bandgap voltage is not totally temperature independent. This paper proposes a solution to this problem by developing a current that has a higher order relationship with temperature to compensate the curvature coefficient, r of the BJT transistor, achieves a voltage reference that has high accuracy and very low temperature drift. It gets a temperature drift coefficient as low as 1.06ppm/℃ within the temperature range of -40~125℃. Benefiting from its insensitivity to the changing of the process, it’s good for engineering. The circuit is made to be transplantable own to the simpleness in modifying the parameter.