SBVS299A April 2017 – September 2025 REF31-Q1
PRODUCTION DATA
The REF31xx-Q1 is a family of series, CMOS, precision bandgap voltage references. The basic bandgap topology is shown in Functional Block Diagram. Transistors Q1 and Q2 are biased such that the current density of Q1 is greater than that of Q2. The difference of the two base-emitter voltages, Vbe1 – Vbe2, has a positive temperature coefficient and is forced across resistor R1. This voltage is gained up and added to the base-emitter voltage of Q2, which has a negative temperature coefficient. The resulting output voltage is virtually independent of temperature. The curvature of the bandgap voltage, as shown in Figure 6-3, is due to the slightly nonlinear temperature coefficient of the base-emitter voltage of Q2.