A band gap reference will have an output voltage that is constant and independent of changes in temperature and power supply and is used as a voltage reference in integrated circuit devices. The output voltage is typically around 1.21V. A band gap reference is created by summing a voltage that has a positive temperature coefficient (increases with temperature) with a voltage that has a negative temperature coefficient (decreases with temperature). The coefficients offset each other and produce a constant voltage over temperature. Band gap references are integral in the operation of analog and mixed-signal fucntions such as voltage regulators and data converters.