This slide shows a shunt reference in an isolated DC/DC power supply. Two of the main criteria make the use of a shunt reference the preferred choice: the voltage reference is powered by an unregulated source with high transients, a strength of a shunt reference, as has been shown; and the output current from the voltage reference to the op-amp is fairly constant, so the weakness of a shunt reference is not an issue. Based on the conditions in this application a shunt voltage reference would be the better choice. The LM4040 shunt reference family is an industry proven and cost effective solution, a standard component in many power supply designs.