A voltage reference is an electronic device that produces a constant voltage irrespective of the loading on the device, power supply variation and temperature. Voltage references are fundamental building blocks in many instruments like data logging systems, digital multimeters, and calibrators. State-of-the-art DC voltage references are large and expensive Josephson voltage standards, operated at cryogenic temperatures. Voltage references are used in ADCs and DACs to specify the input or output voltage ranges. The most common voltage reference circuit used in integrated circuits is the bandgap voltage reference, which uses analog circuits to add a multiple of the voltage difference between two bipolar junctions biased at different current densities to the voltage developed across a diode.
